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The Branner Geological Library
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TREATISE ON GEMS,
IN REFERENCE TO THEIR
PRACTICAL AND SCIENTIFIC VALUE;
A USEFUL GUIDE FOR THE JEWELLER,
LAPIDARY, ARTIST, /t» "'EUR, MINERALOGIST, AND
CHEMIST; AOCOMPANIE: f A DESCRIPTION OF THE MOST
INTERESTING AMEIv^CaN GEMS, AND ORNAMENTAL
AND ARCHITECTURAL MATERIALS.
BY DR. LEWIS FEUCHTWANGER,
AMD imiBBALOCaST; MBBIBER OP TUB 1B# TOBK LTOBUII OV KATDRAI. BZSTORT, AUD OP
mZIBRALOOIOAL SOOimiS OP JBNA, ALIBHBCBO, BVO. BTa BIO.
« t * •
€■ • *
• r *
. • * - • •
NEW YORK :
PRINTED BY A. HANFORD
isa'a
c. -•
. /
>>
210290
Entered according to Act of Congress, in the year 1838, by
LEWIS PEUCHTWANGRR,
in the Clerks office of the District Court of the Southern District of New York.
• •
• • • -
. • • •
• ' •
«
• » ■
m •
Columbia College, )
New York, 26th March, 1838. \
Sir:
I have, at your request, perused the manuscript of your
Treatise on Uie Gems. It gives me great pleasure to be able to
bear my testimony to the care and labour with which this treatise
has been compiled. The work is one which may be usefully
employed by teachers of Mineralogy, and particularly in its
useful applications. To the practical man it cannot fail to be
of great value, from its opening sources of information which, in
this country, are as yet confined to but few persons, and from
the reputation of the authorities whence you have drawn your
&cts. It is, however, in reference to the native minerals and
rocks of the United States, that I conceive your treatise to be
most likely to be eminently useful. I observe that you have
collated the descriptions and localities of American specimens,
which are now to J)e sought in scientific periodicals, or in the
transactions of learned societies. For such searches practical
men have not the opportunities, and scientific men,, although well
aware of the value of our native treasures, are rarely so circum-
stanced as to be able to render them objects of commercial specu-
lation. This part of your task has been laboriously and faithfully
accomplished.
I fam aware that you have experienced a difficulty in being
compelled to write in a language which to you is foreign. On
this h^ul, however, you need not feel discouraged. The language
of science is universal ; and as I have found no difficulty in
understanding every portion of your manuscript, I do not doubt
that it will be equally clear and intelligible to your readers, when
it shall appear in a printed form.
JAMES RENWICK.
Dr. Lewis Feuchtwangrr^
•> '
PREFACE.
Among the many pablications of the present day on the various
subjects of Natural Hist^My, a practical work on mineralogy, as
applied to the Arts, has been much needed in the English
language. Of this general subject the history of the Gems, in
reference to their mineralogical, chemical, and physical characten,
and with a view to serve as a guide to the lapidary, the jeweller,
and the amateur, is one of the most important branches.
The author of the fcdlowing Treatise has, at the solicitation of
his numerous friends, consented to fill with his feeble means that
vacancy in our Uterature. Should he therefore have been so
successful as to realize their wishes, and to contribute in guarding
agaiiist deception and ignorance, and in pointing out those theoret-
ical and practical cautions to be observed in the treatment and
purchase of Gems, he would feel satisfied that his humble and
imperfect efforts are amply rewarded. He has considered the
Gems in their most extended sense, and not treated of the mineral
productions generally called by that name alone, but has included
the Corals, Pearls, and such Bocks as promise to prove ornamen-
tal and useful to architecture. He has drawn the attention of the
reader to those specific characters which distinguish the true
Gems from all other minerals and false stones, the last of which
are now in such general use, and are palmed upon the ignorant as
precious gems, which in truth are remarkably good imitations, and
often require a practised eye to distinguish the false from the
true. The former are now worn by all classes, either from igno-
rance or from the more moderate price at which they can be
afforded, and often present nearly the same appearance as real
Gems. In order to encourage the artist in the manufacture of
those pastes, the author has described the mode of manufacturing
them, according to the best information, and from his own expe-
rience.
The author has been very particular in describing all the
localities of the various Gems and mineral productions suitable for
yi. PREFACE.
ornamental purposes, and particularly those of this country, upon
which the unbounded blessings of Providence have been spread
in the most Uberal manner, in order to awaken the mind of the
young observer to those rich treasures of Nature which are yet
principally hidden beneath the surfiice of the earth, or which may
be left for his future investigation. It is, however, not at all
surprising that those rich natural productions with which the
American soil abounds, are not yet sufficiently known, or even
appreciated, because neither the naturalist nor the student has,
in this country, the opportunity of examining cabinets of speci-
mens of these rich treasures.
It was the author's intention to accompany this work with
plates in illustration of the lapidary's wheels and tools, as well
as of the forms in which all the Gems and minerals originally
crystaUize. He likewise proposed to prepare coloured prints, repre-
senting all the colours of the Gems, such as have been given by
Mr. Mawe, in his Treatise on Diamonds and Precious Stones^
printed in London in 1813. He would at the same time have
extended this work to nearly double its present volume. He has,
however, deferred this task Ito a future occasion, when, after this
essay will have received the sanction of an enlightened^ub
lie, he may feel encouraged to issue another edition. In the
arrangement of the following Treatise, the author has foUowed
the plan [of a small work, published in 1832, by Dr. filum, in
Germany ; but he has drawn other references from the follow-
ing works : —
Haiiy des Pierres Precieuses,
Brard Mineralogie Appliquee aux Arts,
Dumas Chemie AppUqu^e aux Arts, 1821,
Hitchcock's Report on the Geology of the State of Massa-
chusetts,
Gomstock's Mineralogy,
Leuch's Waarenkunde,
Sillimann's Journal.
rf.'
■*■;■"■'
TREATISE ON GEMS.'
PART I.
• ^
•I0I-
INTRODUCTION.
§ I. GENERAL DIVISIONS.
All things in Nature, (material or immaterial,) of which we
take cognizance by our senses, may be arranged under one of two
heads : they are either such as are comprised within space or may
be discriminated by our external senses, as animals, plants, etc. ;
or such as do not possess a form, and are only comprehended by
the inner senses, as doubt, belief, etc. : the latter belong to psychol-
ogy, and the former to physiology, or what we may call physics
by a more comprehensive term. Physics is divided into natural
philosophy and natural history; the latter is divided into the study,
examination, and treatment of organic bodies, such as those be-
longing to zoology and botany, and of inorganic bodies, as for ex-
ample, those belonging to mineralogy.
§ II. DIVISIONS IN MINERALOGY.
The crust of the globe we inhabit consists of inorganic substan-
ces ; minerals in their mechanical, simple, solid, or liquid state ;
and mineralogy, in its strictest sense, treats and considers of the
individual properties of minerals, or those which have reference td
their form, quaUty, and material ; and this part of the science is
generally called oryctognosy : whereas that part of mineralogy
which treats of the constant relation that minerals bear to each
other, in regard to their series, or order of superposition, and also
the geographical distances of their layers, is called geology. That,
part of mineralogy which treats of the application of minerals to
the different arts and other purposes of life is called economical
mineralogy, or mineralogy applied to arts.
10 " TREATISE ON GEMS.
§.iifc ■ PRECIOUS STONES, OR GEMS.
PrecicHis .stones or gems are such minerals as, either from their
beauty 'orether valuable properties, have been made subservient to
the ari^'-or to trade, and are used as ornaments or employed in
j^eilery. In order to appreciate more fully such minerals as may
pos!9Qss superior properties, it is our present object to consider them
ii> Reference to their scientific and practical value.
§ IV. DIVISION OF GEMS.
Gems are generally classed as follows :
ls.t Are real gems, or jewels ; and,
2d. Semi-gems, or merely precious stones. The first comprise
such minerals as combine, within a small space, either vivid or
soft and agreeable colours, with a high degree of lustre, usually
termed fire, as well as hardness; whereas the second possess
these properties in a less degree, often occur semi-transparent
or translucent, and in larger shapeless masses. It is, however,
impossible to draw a strict line between these classes, as the con-
ventional value put upon particular gems belonging to the one or
the other class, also affects their character ; for very often some,
which generally are considered as belonging to the second class,
may be valued, for peculiar properties, much higher than others of
the first class.
Those species of minerals which are generally considered real
gems are the —
Diamond, Garnet,
Sapphire, Tourmalinei
Cbysoberyl, Rubellite,
Spinelle, Essonite,
Emerald, Cordierite,
Beryl^ lolite,
Topaz, duartz,
Zircon, Chrysolite.
The rest are considered, as semi-precious gems. There is
another division, under which the minerals axe arranged according
to their different degrees of hardness. This property will be con-
sidered in its proper place.
TREATISE ON GEM9. H
i V. GENERAL DISTINGUISHING CHARACTER
OF MINERALS.
In order to distinguish the crude and polished precious stones, it
is necessary to describe more particularly the properties and other
peculiarities of the minerals, which we shall now proceed to do.
§ VI. FORM.
All minerals which are distinguished by the form which they
assume within the fdanes they are included in, are called crystals ;
and such regular individual forms, are said to be crystallized. On
the other hand, such minerals as have not acquired this perfect
form, and which appear to us more irregular, are uncrystallized,
and are denominated amorphous.
Crystallography is a highly imp(»rtant branch of study for the
understanding of the practical relation of the crystallized forms of
minerals ; for as these forms or modifications are mostly peculiar to
different species, one mineral may often, with certainty, be distin-
guished from another by a knowledge of the difference between
the forms of their crystals. The great variety of forms under
which the crystals of different substances appear, may all be re*
duced to a few fundamental or primitive forms, which are —
Fig. 1. 1st The Parallelopiped^ which includes the
cube, four-sided prism, rhomb, or any other figure
having six &ees, the two opposite ones being parallel
each other. When its angles are equal in
^>^,.^^ y^ evety direction, and the size of its planes alike, it is
called a cube. When the same figure is extended,
80 as to make the length greater than the breadth, it becomes a
four-sided prism ; and when the angles are oblique, that is, silter-
nately acute and obtuse, it is a rhomb.
Fig. 2.
2d. The Oetahedron, which has eight triangular
feces, four of which meet at points opposite to each
other, and has the appearance of two four-sided
pyramids, joined base to base.
y/^^S.,^^^^ cuboj
/ ^>| havii
r\/Jwitb
Fig. 3.
3d. The regular T^ahedmtj bounded by feur
*«liic|i]e ptauneg, havinf foiff points or angfks, smi six
eogof.
12
TjaEATISE'pN QEMS.
Fig. 4.
<
\ 4th. The regular Hexahedral Prism. A sdid
contained within eight planes; namely, six rectan-
gular, a hexagon, and a six-sided prism, bounded by
a terminal plane at each end.
Fig. 5.
6th. The Dodecahedron, with rhombic faces.
A soUd, containing twelve rhombic planes, a]l similar
to each other.
Fig. 6.
6th. The Dodecahedron, with triangvlar faces*
Twelve triangular planes, exhibiting two six-sided
pyramids, joined base to base.
These forms are the basis of many species of minerals, which
may yet entirely differ in composition from each other; and
although their external appearance may differ from thoie forms,
proper to some minerals, yet each primitive form will always be
found to exist under precisely the same angles.
There are, besides, a vast number of forms under which mine-
rals appear in nature ; but the object of the present essay is only
to refer to mineralogy in its important bearing upon the value of
precious stones : and we will describe, therefore, the crystallization
of the different minerals under their proper heads, when treating
of the individual minerals used as gems. The non-crystallized
minerals exhibit in their external appearance either —
1st. A resemblance to certain natural or artificial products ; such
as a tree, a globe, wire, &c. ; or —
2d. They appear in particular forms, unlike other substances,
such as a compact, sprinkled, or granular one ; and are divided
then into —
1st. Those which have a free formation ; or —
2d. An interrupted formation. Under the first we recognise
globular, clustered, reniform, dentiform, arborescent, capillary,
foliated, stalactiform and prongy. To the ^second we consider as
lidlonging the pseudo-morphous crystal, the amygdaloid, spectre
pelri&ctions or incrustations.
TRSATISE Olf QEWS. 13
§ yn. CLEAVAGE.
All regular formed minerals or crystals are capable of being
cloven or split in certain directions more easily than in others :
and this circumstance is of the utmost importance as regards pre-
cious stones, as some of them may be thus divided into the thinest
leavQjB, and with great facility, whereas it would require consider-
able power to split them in any other direction, and they would^
furthermcnre, exhibit irregular faces. We may also judge from the
cleavagej of the external crystalline formation of a mineral, as the
cloven feces run, generally, parallel to one or the other caystalline
plane. The cleavage of minerals is of essential advantage to the
mineral(^t and lapidary.
§ Vm. FRACTURE.
Fracture exhibits itself in minerals in directions where no
cleavage can be seen or exists, and is either —
1st. Even, if the feces are on a plane without elevations or de-
pressions ;
2d. Uneven ;
3d. Conchoidal, exhibiting conchoidal excavations ;
4th. Splintery, showing small splintery parts on the broken
surface which yet adhere to the mass, but are more transparent ;
6th. Earthy, when the faces show earthy parts on the fracture ;
6th. Knotty, or prominent knots, which are left after the fracture.
§ IX. SURFACE.
The surfeces of the crystallized, as well as non-crystallized min-
erals, exhibit some differences ; they are either —
Ist Smooth;
2d. Striped, exhibiting linear, fine or strong hollows ;
3d. Drusy, presenting small prominent crystals, nearly equal to
each other ;
4th. Uneven ;
6th. Rough; or,
6th. Granular.
§ X. HARDNESS.
The haxdness of minerals forms an important character, it being
uniform in ib» same variety. It is that property by which mineiii^
14 TREATISE ON GEMS.
or precious stones resist impressions of an instrument, or efTorts to
scratch them. There are two modes of testing the hardness of
minerals.
1st. By employing them to scratch such minerals as are known
to be standards for comparison ; or,
2d. By using such standards on the mineral to be examined.
In the first instance we test the hardness on such minerals as the
Diamond, Sapphire, Tq>az, Cluartz, Felspar, Apatite, and Fluor-
spar : or we may use the file, or point of a steel, which is the mode
practised by jewellers, who make use of fine English files, and ac-
quire sometimes great skill in their employment. The soft minerals
and pastes will readily be touched by the file ; whereas. Diamond,
Ruby, and Sapphire are not at all attacked. In mineralogy, how-
ever, a simple table, constructed by Mobs, and called the scale of
hardness, is made use of; and jewellers might derive great benefit
firom its application. This scale consists of a great number of min-
erals arranged together, each of which, in succession, possesses a
degree more of hardness than the one preceding.
The Standard Minerals are as follows : —
1. Talc. 6. Felspar*
2. Gjrpsum, or Rock Salt 7. Cluartz, or Rock Crystal
3« Carlxmate of Lime. 8. Topaz.
4. Fluorspar. 9. Corundum.
6. Asparagus Stone, 10. Diamond.
(Phosphate of Lime.)
We see, by the numerical order, that Fluorspar is 4 and Diamond
10 ; and for determining more particularly the hardness of a min-
eral, the distance between every two members of the scale may be
divided into decimals. In order to test the hardness (rf any mineral,
its corner is applied to the members of the scale, beginmng with
the hardest, so as not unnecessarily to scratch the softo^ ^^^ ^®
ascertain what mineral is readily scratched. We compare then, by
means of a file, the hardness of the mineral to be tested, with the
last member of the scale that has not been scratched; and we judge
firom the resistance which the mineral offers to the file, and fix)m
the noise produced in scratching, whether this mineral is as hard
as, or actually softer than, the last unscratched member of the scale.
Oriental Topaz, fer iitttanoe, will nidmxdXdi the tvm highest mem-
bflrs of the scale, but will the third, theTopu^^f and, tested bf
TREATISE ON OEMS. 15
the fite, we find its hardness not to be under 9 ; since Corundum,
the standard on the scale, gives the same result as the Oriental
Topaz by this test ; whereas, the proper Topaz scratches No. 7.
Piecious stones have latterly been divided and arranged according
3ARD GEMS ; Oa THOSE HARDER THAN QX
Diamond,
'i'opaz,
Sapphire,
Emerald,
Ruby,
Hyacinth,
Chrysoberyl,
Essonite,
Spinelle,
Garnet.
2. SEMI-HARD OEMS.
Rock Crystal,
Opal,
Amethyst,
ChrysoUte,
Chalcedony,
Tiazulite,
Carneleon, and other simi-
Obsidian,
lar ones.
Turqu(rise.
8.' SOFT PRECIOUS STONES.
Those softer than Fluorspar ; Malachite, Amber, and Jet.
i XI. COHESION.
If the smallest particles of a mineral adhere together so as to
represent it in a soUd, fluid, or any other condition, we consider this
effected by the pow^ of cohesion ; and we find that in minerals
which are brittle, the particles are coharent ; in those which are
friable, they are more slightly so. A soUd mineral is said to be
hriitiei if in trying to 6q)arate small particles with a knife or file,
they lose thdr original condition, detach themselves with noise, and
fly about in form of powder.
2d. Pliable^ if the separate particles remain in their condition.
3d. Mild^ if those partides, after being detached, remain on the
cutting instrument
4tb. Extensible^ if the mineral may be beaten into plates or
drawn into wire.
6th. FlwMej if the detadbed particles that have been bent, will
not resume their former position.
16 TREATISE ON GEMS.
6th. Elastic^ if, after being bent, they will resume their former
position.
A liquid mineral may be either tough or thickly liquid. The
degree of the cohesion of a mineral depends upon the hardness
which it possesses, and this property has been already considered.
§ XII. SPECIFIC GRAVITY.
The specific gravity of a body is its weight, when compared
with the weight of a quantity of water equal to its own bulk.
When a mineral is suspended in water, and weighed, it is lighter
than when weighed in air, by the weight of a quantity of water
equal to the bulk of the mineral so suspended. It is obvious, that
a mineral, bulk for bulk, as heavy as water, could not sink in it ;
but if it should sink, its weight must be diminished by exactly that
of the quantity of water it displaces. In order to find the specific
gravity of a substance, it must be weighed in air by a hydrostatic
balance, or by a common balance, and then weighed in water,
when its specific gravity may be found by calculation, viz : by di-
viding its weight in air by its loss in water. Specific gravity in
minerals is a very remarkable property ; since different substances
possess, in most all instances, a different gravity ; whereas all vari-
eties of one and the same substance possess nearly the same specific
gravity. For determining the specific gravity of minerals with the
hydrostatic balance, we proceed, for instance, as follows : — an un-
known mineral having been weighed first in the air, is then fasten-
ed by means of a hair, and weighed in water. Its weight in the
air we state at 17.65, in water 12.35. The loss in water is, there-
fore, 6.30 ; and this number indicates the loss of so much bulk
of water displaced by the mineral, considering the specific gravity
of water 1.00 ; dividing 17.65 by 5, makes it equal to 3.63, which
is the exact specific gravity of the mineral, and which is that of
Essonite. Instead of a hydrostatic balance, we may as well use
Nicholson's hydrometer, a simple and very convenient instrument,
consisting of a hollow glass cyUnder (A,) and two dishes (B and C)
filled with lead, in order to keep the instrument upright. The hy-
drometer is put into a glass vessel (E,) filled with water, and used
as follows :
1st The weight is determined, which is required to sink the
instrument to mark D in water. 'V
<*.
TREATISE ON GEMS. 17
2d. The mineral is put in the dish A, over the weight noted, that
is required, in addition to the mineral, to sink the hydrometer to D.
3d. The same experiment is repeated, by putting the mineral,
after being moistened and washed with water, in the dish C ; and
now is A — B the weight of the mineral in the air, and C — B the
weight of a quantity of water equal in volume to that of the mineral.
For instance, let A = 32.8
B = 7.3
C - 15.8
there is (A — B) 32.8 — 7.3=25.5 the weight of the mineral in the air.
(C — B) 15.8 — ^7.3 =8.5 the weight of an equal quantity of water,
and proceed 8.5 : 25.5 =1 : x
X = 25.5
8.5
= 3.00, which is the proper specific gravity. For
determining the specific gravity of substances or minerals lighter
than water, or which float in water, it is necessary to adhere to the
same method by the hydrometer. A heavier body, such as lead^
after determining the difference of weight, within or without the
water, of both together, and then of the heavier body alone, the
specific gravity of the lighter substance is the result. And for de-
termining the specific gravity of liquids, by means of the hydrosta-
tic balance, a glass ball is applied to one of the arms, (its loss of
weight in pure water being known,) and, dipping the same in the
liquid to be examined, any addition or abstraction will show the
specific gravity of the liquid. The hydrometers of Beaume for the
different liquids to be examined, are employed with satisfactoiy
results.
That the specific gravity of minerals has been known as far back
as tW thirteenth century, and was applied by the Oriental nations*
for /determining the character of precious stones, is sufiSciently
proved by a work written in that century by Mohammed Ben Man-
ner. In fact, the specific gravity is ofl«n, in connexion with the
colour, quite essential in determining the nature of a gem.
§ Xin. COLOURS.
The colour of minerals and precious stones is one of their most
obvious and.flCdking properties ; but yet it is very difficult to diatin-
c
18 TREATISE ON GEMS.
guish accurately a mineral by this, on account of the colours very
frequently being accidental, or depending upon the presence of cer-
tain metallic oxides. The nature of tlie colouring principle was
well known in former ages, but nought but erroneous views were
entertained of the same. Thus, &r instance, it was beUeved that
gold and tin were the colouring pirinciple of garnet ; and Boyle,
several centuries ago, speaks of a metaUic spirit that communicates
the colour to precious stones. Mineralogists have fixed eight pri-
mary or fundamental colours, besides all the different shadings from
one colour to the other, on account of the colours being reflected
from the different substances. They are generally divided into —
1st, Metallic ; and,
2d, Non-metallic colours.
Metallic colours are the following :
Copper, red. Silver, white.
Bronze, yellow. Tin, white.
Brass, yellow. Lead, gray.
Gold, yellow. Steel, gray.
Iron, black.
The eight primary of the non-metallic colours are as follows : —
White, Gray, Black, Blue, Green, Yellow, Red and Brown. And
the shades of each of these primary colours are —
1. WHITE.
Snow-white, Grayish-white,
Reddish-white, Greenish-white,
Yellowish-white. Milk-white.
2. GRAY.
Bluish-gray, Greenish-gray,
Pearl-gray, Yellowish-gray,
Smoky-gray, Ash-gray.
3. BLACK.
Grayish-black, Brownish-black,
Velvet-black, Bluish-black. |
Greenish-black,
4. BLUE.
Blackish-blue, Prussian-blue,
Lasur-blue, Sky-blup^
Indigo-blue, Yiolet-tiue,
TREATISE ON GEMS.
19
Smalts-blue,
5. GREEN.
Lavender-blue,
Verdigris-green,
Seladon, or Green Earth-
green,
Asparagus-green,
Mountain-green,
Garlic-green,
Emerald-green,
Lemon-yellow,
Sulphur-yellow,
Straw-yellow,
Wax-yellow,
Orange-yellow,
Carmine-red,
Scarlet-red,
Crimson-red,
Cochineal-red,
Columbo-red,
Cherry-red,
Peach-red,
Chesnut-brown,
Reddish-brown,
Clove^brown,
Hair-brown,
Blackish-brown,
Grass-green,
Epidote-green,
Olive-green,
Blacldsh-green,
Oil-green,
Siskin-green.
6. YELLOW.
Honey-yellow,
Ochre-yellow,
Wine-yellow,
Isabel-yellow.
7. RED.
Rose-red,
Brownish-red,
Flesh-red,
Aurora-red,
Hyacinth-red,
Brick-red,
Blood-red.
8. BROWN.
Ydlowish-brown,
IlJBca-brown,
Lignite-brown,
Silver-brown.
The precious stones possess the colours in the highest perfection,
and their principal and intrinsic value depends mostly upon this
property ; as most gems occur of various colours, the following
taUe will exhibit them, along with their specific gravity —
LIMPID GEMS.
ZorcoQi , -
Sapphirdi 5#A%
SPECIFIC ORAvrrv.
4.41 to 4.60
3.9 4.00
?
20 TREATISE ON GEMS.
Diamond, 3.6 3.6
Topaz, (Pebble) . - - . . 3.49 3.56
Rock Crystal) (False Diamonds, Lake
George, Trenton Falls,) - - • - 2.69
Beryl, Aquamarine, - - - 2.67 2^8
RED GEMS.
Zircon, Hyacinth, - - - 4.41 to 4.50
Garnet, (Oriental Garnet) - - - 4.0 4.2
Sapphire, Ruby, . - - - 4.0
Garnet, Bohemian Garnet. Pyrope, - 3.7 3.8
Spinelle, Ruby Spinelle, Ruby Bsdaise, - 3.58 3^4
Diamond 3.5 3.6
Essonite, 3-5 3.6
Topaz, Brazilian Topaz, (often burnt) - 3.52 3.56
Tourmaline, Siberite, Rubellite, - 3.03 3.10
Rose Cluartz. Bohemian Ruby, - - 2.61 2.63
Cameleon, - - - - 2.5 2.6
YELLOW GEMS.
Zircon, 4.41 4.50
Sapphire. Oriental Topaz, - - 4.0
Chiysoberyl, 3.59 3.75
Topaz. Brazilian, Saxonian, and Syrian
Topajz 3.50 3.56
Diamond, 3.5 3.6
Beryl, 2.68 2.71
Rock Crystal, Citron, - - - 2.60 2.69
Fire-opal, 1.90 2.12
GREEN GEMS.
Zircon, 4.41 4.50
Sapphire, Oriental Chrystolite, and Emerald 3.9 4.00
Malachite, - - « - . 3.67
Chrysoberyl, 3.59 3.75
Spinelle, 3.58 3.64
Diamond, 3J 3.6
Topaz. Aquamarine, - - - 3.49 3.56
Chrysolite, 3.33 3.44
Idocrase, ------ 3.08 3.40
Tourmaline, (Brazilian and Maine,) - . 3.00 3.30
Emerald, 8.67 2.73
TREATISE ON GEMS. 21
Beryl, 2.67 2.71
Prase, - 2.66 2.68
Heliotrope 2.61 2.63
Chrysoprase, , - . . - 2.68 2.60
Felspar, Amazon Stone, - - - 2.60 2.60
BLUE GEMS.
Sapphire, 3.90 4.00
Disthene, (Kyanite,) - ' - - 3.63 3.67
SpineUe, 3.68 3.64
Diamond, 3.5 3.6
Topaz. Brazilian Topaz, - - 3.49 3.56
Tourmaline, Indigolite, - - - 3.00 3.30
Turquoise, 2.86 3.00
Beryl, Aquamarine - - - - 2.67 2.71
Dichroite (loUte,) . . - . 2.68 2.60
Haiiyne, 2.47
Lazulite, 2.30
VIOLET GEMS.
Garnet, 4.0 4.2
Sapphire, Oriental Amethyst, - - 3.9 4.0
SpineUe, 3.68 3.64
Axinite, 3.27
Tourmaline, 3.00 3.30
Amethyst, 2.66 2.78
BROWN GEMS.
Zircon, 4.41 4.60
Garnet, 4.00 4.20
Essonite, . - . - . 3.63 3.60
Diamond, 3.60 3.60
Tourmaline, - - - - - 3.00 3.30
Smoky Cluartz, . . - . 2.69 2.70
BLACK GEMS.
Diamond, 3.50 3.60
Tourmaline, ----- 3.00 3.30
Rock Crystal, Morion, - - - 2.69 2.71
Obsidian, 2.34 2.39
KtchCoal, 1.29 1.36
Canndl Coal, - - - 1.23 1.27
22 TREATISE ON GEMS;
,GEMS DISTINGUISHED FOR THEIR VARIOUS SHADINGS
OF COLOUR AND LIGHT.
Gkmet, - ... - - 4.00 420
Sapphire, Star Sapphire, - - - 3.90 4.00
Chrysoberyl, 3.70 3.80
Hypersthene, 3.38
Labrador Spar, - . - . 2.71 2.75
Dichroite, - - 2.68 2,60
Cat's-eye, 2.56 2.73
Adularia, 2.50 2.60
Felspar, 2.50 2.60
Precious Opal, 2.00 2.10
Hydrophane, - - - - - 1.90 2.00
A number of the precious stones do not possess a fixed colour,
but merely a tinge or shade of a colour which we distinguish from
one another by the terms, dark, high, light and pale coloured or
tinged. Another distinction consists in precious stones possessing
either one or more colours or a varigated colour, or being spotted,
painted or stained with different colours ; these latter characters,
however, more properly belong to the semi or common precious
8((mes, than to gems.
§ XIV. LUSTRE.
The quantity of light which is reflected from the surfece of
minerals and precious stones, is indicated by the lustre ; and this
18 an important character for distinguishing minerals, inasmuch as
U k almost uniform in the same species. It exhibits itself oither —
A, in the strength ; or,
B, in the kind. '
The first depends in precious stones, on the beauty of their sub-
stance, and the tnanner in which they are cut and polished ; and
we distinguish^-
1, highly hislrous; 4, shining;
S, lustrous; .S^^ faint;
' 3, Uttler lustrous ; and the h%l^' degree of
lustre kcalled fiery.
The kindaitf lustre are-^
1, metallic; 2, adamantine;
TREATISE ON GEMS. 23
3, resinous ; 6, pearly ;
4, vitreous; 6, oily.
Often we perceive the transitions from one lustre into the
other : and we describe a mineral as possessing the lustre betweea
the adamantine and vitreous lustre, and approaching to the peady
lustre.
§ XY. TRANSPARENCY.
The capacity of minerals and precious stones to permit the pas-
sage of the rays of light through them, so that an object held on
the one side may be clearly seen on the other, is called its transpa-
rency : and according to the extent in which this property is pos-
sessedy we divide it into —
1st. Transparent, as where the object is perfectly visible ;
2d. Semi-transparent, where not distinctly visible ;
3d. Translucent, where the object is but feebly seen through,
and yet is clear towards the light ;
4th. Translucent on the edges ; and,
6th. Opaque, where no light at all is transmitted through the
mineral.
§ XVI. REFRACTION.
When the rays of Ught pass from one substance (rarer medium)
into another (denser medium), they are always refracted pr bent
towards a perpendicular Une passing through that substance (me-
dium) : and so also n^en the rays pass from a denser into a rarer
medium, they are refracted in a contmry direction, or from such a
perpendicular ; and objects are multiplied when seen through the
inclined contiguous stirfeces of any transparent medium. The
light coming from the object being refracted by the oblique sur&ce,
passes to the eye in a different direction from that of the real object,
and thfflre are as losxkj images seei^ as there are oblique planes*
According to the manner in which the rays are refracted, the
power is divided intO' —
1st, simple ; andj
2d, double refraction.
An object may be seen double or treble; it is yet the simple
refractioii^^ince the direction of the rays of light are only changed
by the diiection in which they hajqpen to strike the transparent
24 TREATISE ON GEMS J
surface. When* an image of a single object is doubled, if seen
through the parallel surface, it is called double refraction. Almost
all precious stones possess the power of double refraction in a greater
or less degree : we may distinctly see the single refraction in quartz
of a prismatic form, and that of double refraction in the rhombic
limestone, called the Iceland spar. But all precious stones do not
possess this property in the same degree ; and on that account we
specify the same by calling it —
a, treble ;
b, moderate;
c, high ; and
d, very high degrees of double refraction.
This property, depending upon the interior structure of the min-
eral, is of intrinsic value in testing the most valuable gems. But
it has always been difficult in practice to determine with accuracy
this character ; for the observer is often disappointed in his experi-
ments. Fissures in the substances partly contribute to the disap-
pointment, and sometimes the general structure of the mineral will
not permit of an accurate test, as it may not yield the proper face or
facette, or the plate may be too thick for obtaining the proper refrac-
tion ; it therefore cannot be employed without much practical skill.
§ XVII. PLAY OF COLOUR.
The property of many precious stones to display different colours
in smaller or greater points of brilliancy, when the rays of the sun
are directed towards them, or by changing the position of the gem,
is called a play of colours : such we perceive in the Diamond, pre-
cious Opal, and Labrador Spar.
§ XVIII. IRIDESCENCE.
If the fissures contained in the interior of a transparent precious
stone, represent coloured rings, resembling colours of the rainbow,
the appearance is called iridescence.
§ XtX. CHANGE OF COLOUR.
The property of certain precious stones to display two diflferent
colours, if held in different directions, is called the change of colour:
such we observe in the Cat's-eye, Moon-stone, and lolite ; also, in
the Chrysoberyl. This property has generally been termed opal-
escence, which, in my opinion, is the same as iridescence.
TKEATISE ON GEMS. 25
• . . § XX; LOSS OF COLOUR.
Many precious stones, when exposed more or less to atmospheric
air, and also from the oxydation of the colouring [Hinciples ccmtained
in them, lose their colour ; which may, however, very often be
restored, either by laying them in a dark or moist place ; as in the
case of Rose Q,uartz and Chrysoprase ; or they may be restored by
leaving them some time in oil, as is done with the OpaL
§ XXI. LUSTRE SHINE.
A soft waving shine of lustre is often perceived in the interior of
several gems ; also that of a star, such as we detect in the Star
Sapphire.
§ XXn. PHOSPHORESCENCE.
Many precious stones posses? the property of giving a greater or
less distinct light, either by mechanical means, artificial heat, or the
effect of the rays of the sun : this is called phosphorescence. The
Diamond, for itistance, if merely rubbed with wool, or a brush,
exhibits this property. Other precious stones, if rubbed together^
such as two pieces of Ctuartz : others, again, by being scratched
with iron, steel, or copper, such as Dolomite and Blende. Some of
them, such as Diamond, White Topaz, and Fluorspar, become
phosphorescent by warming with the hand ; and others again by
exposing them to the rays of the sun, such as Dicmaond, Amber,
Fluorspar, and several other gems* The light representing the
phosphorescence is white or coloured, and but momentary in its
duration.
I
§ XXra. ELECTRICITY.
Many precious stones become electric by friction, pressure or heat.
Electricity manifests itself by attracting or repeUing light movable
substances. There are two kinds of electricity —
1st. The positive ;
2d. The negative ; vitreous or resinous electricity ;
and, according to their sur£sLce when either smooth or rough, all
gems may be made electric : many of them, such as Q,uartz, MicaE,
Sapphire, and Barytes, when rubbed only with the dry hand or a
piece of siQe^ woollen or for : others again, such as Tourmaline or
Topaz, by bekig heated ; the latUr are said to be pyrpdectric^ ot
26 TREATISE ON GEMS.
electric by heat Most crystals acquire positive electricity at one end
and negative at the other. If they terminate in a different number
of feces at each extremity, the end having the greatest number of
faces is always poritive.
All polished stones acquire positive electricity by friction ; while
if the same stones (except the Diamond) have their polish destroyed,
they acquire negative electricity. The most simple apparatus by
which electricity may be ascertained, is a brass or copper needle,
with two small balls at each end, and which being isolated j is to be
suspended on a steel point. In experimenting, the gem to be tested
being rubbed, and then brought near one of the balls, the strength
or power of attracting the same indicates the degree of electricity
contained in the body. The length of time that the electricity ac-
quired by rubbing maybe retained, varies in different minerals and
gems ; and as the latter are all electric, this differing in the length
of time, may sometimes be used to distinguish one gem from an-
other. Abbe Haiiy found, in his experiments, that many precious
stones lose their electric power after a few moments, whereas others
will retain it for twenty-four hours. The Brazilian Topaz affected
the needle even after thirty-two hours.
§ XXIV. MAGNETISM.
The properties by which minerals act upon the magnetic needle
is called magnetism. There are but few gems that possess this
property ; the Chrysolite, Essonite, and Garnet owe their magnetic
properties to the metallic oxides they contain. A common mag-
netic needle is used for testing its presence.
§ XXV. TOUCH.
Precious stones produce a peculiar impression on the senses ; and
most gems unpart a cold feeling when touched, indicating, at equal
temperatures, a much colder feeling than pastes.
i XXVI. TASTE AND SMELL.
Many minerals have a taste, on touching with the tongue, and
they are—
1, As Vitriol; 4, Alkaline; 6, Bitter;
2, Sweetish, as Alum ; 5, Cooling ; 7, Urinous.
3, Saline;
TREATISE ON GEMS. 27
Many minerals emit a smell on rubbing, or merely heading them
in the hand ; such as Bitumen, Pyrites, Carbonate of Lime, Bary-
tes. Gypsum, Q,uartz and Coal.
§ XXVn. CHEMICAL CHARACTERS.
Although mineralogy could not exist as a science, without the
aid of chemistry, and whole systems or classifications have been
established, as well as the constituent parts of minerals determined
by knowledge of chemical characters, still it is difficult to resort to
chemical means for distinguishing the gems or precious stones, as
they would be destroyed by such an examination, and we can, for
that purpose, only employ splinters or fragments. The most simple
mode of proceeding is to test —
Istj^JTheir greater or less fusibility, with or without a flux ;
2d, Their behaviour before the blowpipe, an instrument highly
convenient, and indeed indispensible to the mineralogist ; and,
3d, The action of the acids upon them.
All of these means, however, have not an effect upon all gems,
as many of them, for instance, are either infusible, or fusible with
the greatest difficulty by the addition of a flux.
i XXVffl. COMPOSITION OF GEMS.
The attention of writers, as far back as 1502, had been directed
to the establishment of some hypothesis as to the composition and
origin of the gems, and many &bulous views were entertained in
respect to their formation.
There was also connected with some hypothesis, a species of me-
dical superstition as to their effect. Boyle (1672) thought that all
gems were originally formed from clear limpid water, and that they
received their colour and other properties from their metallic spirit
Others considered a peculiar earth, called the noble or precious
earth, as the principal ingredient of the precious stones. Bruckman
(1778) lecognizied Q,uartz as the principal of the gems. Bergman
thought that gems were all composed of the same ingredients, such
as alumina, silex, and lime, and that the different proportions pro-
duced the different species ; and the older mineralogists determined
the character of the gems by their hardness, lustre, structure, and
resistance to acids. But modem chemistry has ascertained the^com-
ponent paitSi amd othec chaiacters of gemsy with more certainty;
28 TREATISE ON GEMS.
and it is satisfiictorily proved that the principles they contain are
the earths, such as silica, alumina, and lime ; that some contain a
peculiar earth, (such is the case with the Zircon, Emerald, and
Ghrysoberyl,) and that the Diamond, at the head of gems, consists
of pure carbon, &c.
§ XXIX. GEOLOGICAL CHARACTERS.
The origin, locality, and geological characters of gems are
various ; it was formerly supposed that the trap formation was their
matrix ; but it is ascertained that we find them distributed in rocks
of different ages and kinds, either as accidental mixtures — such as
Garnet in gneiss and micaceous scbiste — or in drusy cavities, such
as the Emerald, which occurs in druses of argillaceous slate and
micaceous scluste; and many precious stones are found in gangues.
Many gems are found at a distance from their original bed, on
secondary or diluvial strata, or in the beds of rivers, mixed with their
sand. Thus, Zircon is found in Ceylon in regular beds ; and like-
wise we find in Ceylon, after much rain, the Topaz, Zircon, and
other gems. This happens more frequently in the beds of the rivers,
and then the gems appear often in the shape of pebbles, showing that
those hard stones, carried away from their original beds, have been
rolled and rounded by the streams and rivers, although they retain
sometimes their crystalline structure, on account of their hardness.
§ XXX. GEOGRAPHICAL DISTRIBUTION.
The locality of the gems bears some highly interesting characters,
inasmuch as we may sometimes judge, from their appearance of the
climate of their locality ; and it seems as if the countries of the torrid
zone had been particularly favoured by nature in producing the
most precious gems, or that those hot-beds were more propitious to
the formation of the blossoms of the inorgamc world. Comparing,
for instance, Spinelles and Zircons, from Siberia, with those of
Ceylon and Peru, we find the first to be dark and of impure colour,
as if emblematic of a cold, unfriendly, northern climate ; whereas,
the latter glitter with full brilliancy, and possess all those properties
and beauties for which gems are so highly esteemed. Ofiten, too,
we find the gems collected in particular countries, or isolated spots
of our globe, such as the most precious gems from the East Indies
and Brazil, where, singular enough, they ock:ur with the precious
TREATISE ON GEMa 29
metals : as, for instance, the Diamond in company with gold and
platina in Brazil. Some of the gems have likewise been hitherto
discovered in a single spot on one continent only, and are then ex*
hausted : such as the Rubellite, in Maine, United States ; the lolite
in Connecticut, United States, and the Lazulite ir Persia.
i XXXI. PRACTICAL DIVISION AND NOMENCLA-
TURE OF GEMS.
Artists have not profited in their arrangement and nomenclature
of the gems, of the advanced state of mineralogy, as a science ;
and although they have been newly classified by the mineralc^ts
according to their scientific characters, the practical artist arranges
them according to those properties that principally attract the eye :
such as colour, transparency, and lustre. Gems have, in conse-
quence, received their names from their colour : as Ruby, fiX)m its
red colour ; Sardonyx, Yellow Onyx ; since they often call gems
by such gloss or colour as a distinctive property of different species
by the same name, according to their colour. For instance, they
call the Corundum, the Spinelle, or the Topaz, if of a red color,
Ruby ; if blue. Sapphire ; if green. Emerald ; if yellow. Topaz,
and if violet. Amethyst : and thus gems of the same colour, but of
different composition, were arranged under the same head. The
artist confounds under the name of a Brazilian Ruby, either a light
rose-red Spinelle, or a Topaz approaching to the red colour. The
name of a country or locality, is often sufficient to give name to
gems of the same colour, but of different shadings, and of more or
less vivid lustre. Thus, by Oriental Chrysolite is meant a yellowish-
green Sapphire, and by Saxonian Chrysolite, a pale wine-yellow
Topaz. Many gems have always been known under the name of
Oriental gems, partly because they were first obtained in the East,
and partly because they, stood, firom their excellent properties, in
higher estimation than those from any other country. Those from
the East were likewise called ^^ Oriental," in opposition to those less
valuable, which were called "Occidental" gems. Subsequently^
all gems of superior qualities were called Oriental gems, even when
their locality was not in the East. Thus, for instance, they call
that precious Opal, so well distinguished for its beautiful play of
colours, the Oriental Opal, although it is never found there ; hke-
wise, the pureiiir wd most valuable Emerald, which in great perfec-
tion only occuiB ia PerU; is known as the Otveii\a\E^f£i<sa^^
30
TREATISE ON GEMS.
§ XXXn. HISTORY OF THE GEMS.
ThoB6 precious stones, which are now called gems, were known
in ancient times but very little, if at all. The first notice given
of them is in the Bible, where it is stated that the high priest wore
Olio stone on his gold scarf, and twelve gems set in gold plate, called
the Urim and Thummim, each of which represented a tribe. It
appears that the Hebrews borrowed the names of their gems from
th3 Egyptians, and few of those gems named in the holy scriptures
correspond in any respect with those at present known in our min-
eralogical books, with the exception of the Sapphire. The Greeks
appear to have been but htde acquainted with the gems, as they
did not use them as ornaments in the Trojan wars ; and Homer,
when speaking of the treasures of those times, does not make any
mention of the gems. Theophrastus and Pliny have described
some gems of their time but very imperfectly and confusedly ; and
their descriptions are so replete with vain fancies, that it is difficult
even to identify any from their descriptions. They began then to
attribute most wonderful powers to the gems ; to give fabulous des-
criptions ; the most singularand perverted views in regard to their
origin ; and it was said that they had great influence upon health
and beauty, riches, honour, and good fortune. They were called,
when worn, Amulets. They were brought in connexion with the
planets, the twelve constellations, and the seasons of the year ; and
a certain gem was worn each month, which was said to have dur*
ing that term, its peculiar influence and healing virtues. Such
superstitious notions have been transmitted to our times. The gems
corresponding to the different months, and also to the twelve Jewish
tribes, are the following : —
January
Hyacinth
-
Dan.
February -
Amethyst -
-
Gad.
March -
- Jasper -
-
Benjamin.
April -
Sapphire
mm
Issacfaar.
May
- Agate
-
Naphtali-
June -
Emerald
#
Levi.
July
Onyx
-
Zebulon.
August
Carneleon
-
Reuben.
September
• Chrysolite
-
Asher.
October
Beryl -
-
Joseph.
November
Topaz
- .t
Simeon*
December -
Ruby -
~«»
Judah.
TREATISE ON GEMS. 31
Artists have made certain alterations between some gems cor-
responding to the months, and the tribes represented in the Urim
and Thummim, and they consider May to be represented by
Emerald;
June, - - by Chalcedony, Onyx, or Agate ;
July, - - Carneleon;
August, - - Sardonjrx;
October, - - Aquamarine ;
December, - Ohrysoprase, Torquoise, or Malachite.
In the early ages similar views were entertained in the East,
and many of them are yet prevalent. Thus, among others, the
Persians beUeve that Spinelle affords joy, and protects them against
bad dreams. The Indians believe in the eflScacy of large Dia-
monds to bring them back to their &miUes. (The Rajah of Mat-
tan, a district of the Western Borneo, possessed a Diamond of
367 carats.) The Ruby is esteemed as a talisman in the East,
which is not shown ever willingly to friends ; it is considered
ominous if it contain any black spots. The Chinese, on the con-
trary, present the same stone as a testimony of friendship. The
Peruvians adore the Emerald as their deity. Many of these
fiibulous notions were probably brought from the East to Europe ;
for we find, in the middle ages, similar views entertained by
Marbodus, Bishop of Rennes, who wrote a book on the miraculous
powers of the gems. The twelve Aposdes were likewise repre-
sented symbolically by the gems, and they were called ''the
Apostle Gems ;" such as —
Jasper, - - for St. Peter ;
Sapphire, - - St. Andrew ;
Chalcedony, - - St. James ;
Emerald, - - St. John ;
Sardonyx, - - - St. Philip ;
Carneleon, - - St. Bartholomew ;
ChrysoUte, - - St. Matthew ;
Beryl, - - - St. Thomas ;
Chrysoprase, - - St Thaddeus ;
Topaz, - - - St James the Less ;
Hyacinth, - - - St Simeon ;
: Amethyst, - - St Matthias.
The ancient% induced by the beauty of the gems — such as the
32 TREATISE ON GEMS.
pure and deep colour of the Emerald, the vivid and high lustre of
the Diamond, and the agreeable reflections of the Opal — ^had
commenced using them as ornaments and jewellery, and they
took pains to adapt them to their purposes. Although they did not,
in those times, understand the cutting and polishing in the same
manner as in the present, yet they endeavoured to work them in
all possible shapes, by rubbing off the comers, or polishing the
natural feces. They generally fixed the gems on strings ; they
also tried to carve figures representing deities, religious costumes,
historical events, exploits of celebrated generals, or the heads of
great men.
§ XXXm. SCULPTURE IN GEMS.
The art of carving was well known to the ancients, and those
were called gems, in the proper sense of the word, which had
figures or letters engraved on a very small compass, the workman-
ship of which we, at this day, cannot help admiring.
Gem-sculpture, or the glyptic art, (or lithoglyptics,) is the art of
representing designs upon precious stones, either in raised work
(cameos) or by figures cut into or below the surface (intaglios.)
The first were most natural to the rising art, and were used as
seals ; whereas the latter were used as ornaments, for which the
most precious materials were employed, according to the state of
the art. They did not understand engraving in Diamonds, and
few in other gems: they employed only the softer stones, the
common precious stones, such as Carneleon, Onyx, Jasper, &c. ;
they also used paste, or artificial coloured glass composition, for
their engravings. Their mode of working was very simple : the
polishers prepared their stones on a plate, by means of the powder
of harder stones, either round, oval, flat, or in shield form, accord-
ing to the designed subject, and then left to the sculptors the sub-
ject of the engraving, which was done by means of iron, or
Diamond splinters mounted in iron. It was not until the year
1500 that Ambrosius Caradossa first discovered the method of
cutting the Diamond. He prepared the figure of a patriarch for
Pope JuUan II. He also discovered the first traces of sculpture
among the Jews, Persians, and Egyptians. In the traditions of
the Iply Scriptures, Moses, for instance, had the names of the
tweltii tribes of Israel engraved on the gems used by the high-
TREATISE off BiUS. 3$
priest. Solomon possessed a s^l : Alexander presented his seal
to Perdicas. Augosttis had a sphinx engralred od his i^l ; \^t
the Indians and I^ersians engraved rhostly titythologii^ amvhaU
or priests in their gems ; the! Egyptians, beetles^ which tbej^
adored, and which are called the scarabsei* '^ Abraxes'^ were thii^
oldest gems, which had the representation of ftiMastieal sttrima^
with the above word in the Greek langtiage. engraved on thtthf
The Phenicians, Hetrurians, and Gr^kii learlied the art tif
carving from the Egyptians ; and froih thchCn it was carried to th^
Rdmatis, where it was lost, with the declined of the empire, Ih tb#
fifteenth centnry, under the Popes Martin Y. and Paul 11. Thef
art was revived again by some fcigitive Greeks in Italy. G^at
merit is also dde to the Mediciand for the revival of tb^ art ; ikikl'
Giovani was considered the first in Italy. The talisman^ eft
carved gems bearing Arabian' letters, belong tx> those tixi^est
Precicfns stone»rwith layers, veins, or such as Onyx, Sardonyi^,
&c., were employed by the ancients, with greAi skiU, in the carv-
ing of cameos, where we find the head of one cobur, and haif
and dress of a difierent cdour carved out of the other layer of the
stone. Terjr often the subjects were mythological^ and this mode
of ei&rving or sculpture has been imitated by mcfdera 2£rt]S(s. It is
soriietii^es with difficulty that we are enabled to distinguish the
aticient from the modem works, and the only authentic authority
for the Antiquity of the cameo or intaglio is its excavation front
ancient monnments, exeept in a few instances, where we may be
able to judge by coisiparisou of the difierence in antiquity ; by
observing whether or not they are unnaturally, or stiffly done ;
h^U^ large heads, hands, and fy^ stifi* streaks resemUing the hair,
oi th^ eyes drawn in the lei^gt^, Sec. We find that some gods,
representing the peculiar gem^, (such we see all sculptures of
Elacchus^ and what relates to faim,) were executed in Amethyst,
bekig the colour of wine ; and dU tiymphs, Neptune, or fish, in
jltfifusimdrine, &c., the colour of ^BUsr* We find also^ in Geriiiaiiy^
Udice^ of scttlptnre, m the fourteenth and sixteenth centuries 4 the
ot^leBt known artst, Daniel Engelhard, at Nuremburgh, died in-
1652 ; also Lucas KiHan ; and the best artist, Nater^ died inh
1705. England and France had likewise very .distingMislied
artists in carving. A ftiU history of gem-sculpiure may beffiaiad
in the Encydbpedia Americana, pp. 403—406. ^. ^T'V -
34
ntUTISG ON G£H9.
I XXXIV. ON GRINDING.
The art of grinding gems ia of more modern origin ; it consisu
in cutting tbe geme, and other precious atones kts figures, bounded
by maof planes, and by polishing the &ce8 thus formed, increasing
their lustre, tcansparency, and other raJuable properties. This
GMistitutes tbe work of the lapidary. In the year 1290 a society
of lapidaries was formed at Pe^, and in 1385 there were diamond-
cutters at Nuremburgh ; but it was not until 1456 that LudwigVan
Betgen invented the art d' poUsbing the Diamond with its own pow-
der ; and they then began to cut tbe gems according to mathemati-
cal principles, and brought the art in modern limes to the greatest
perfection. There is a great difference in gems, (which are mostly
procured from tbe Indians in a rough or polished state.) easily to
be detected by their imperfections. They look more upon the size
of the atone than upon the cut, which is generally irregular and
dertnd of symmetry. We observe this in the two celebrated
Diamonds of the Shah of Persia, the Dariainur — brilliant sea — >
(1 aa.d 1 a) and the Kuinur — brilliant mountain— {2 and 2 a:)
fJjMiMll'itl.ll.lllBA.IljAl
.UUItHlAl.Ul^l.l.l.l.l.t.l.U
^'iB.r.tr.v.v.y.ttif.v.v.v;
z:
iltlT^TlTtr^TLT^1 ,r(r(Titi1it!r^
tht one is worn on the left arm, and the other on the right knee.
By looking at the subjoined representatbn of the Dlamwid
belonging to the Crown of France, which weighs one hundred
aad thirtjT'AX and a quarter carats, it fbuttAen lines bng, thirteen
TREATISE ON OEMS. 35
and a quarter lines broad, and* nine and a quarter lines thick^
and which is known by the name of Regent^ we can mora
distinctly discriminate the irregular and unmathematical cut
r ^
V )
The gem-grinders are divided into three classes : Ist, the Dia^
mond; 2d, the gem ; and, 3d, the jewellery grinders.
The Diamond grinder divides his work into — a, sHtting or
cleaving ; 6, cutting ; c, grinding ; and dy polishing.
Before operating upon Diamonds, some preliminary experhnents
as to their soundness are made : for very fine imperceptible fissures
may, at the end of a laborious grinding, terminate either in crack^
ing or spoiling the stone. An examination for this purpose is made
in one of the two following modes : either the Diamonds or any
other gems to be examined, are steeped in Canada balsam, or in
oils of sassafras or anniseed, in which fluids they are well turned
around, whereby the minutest fissure, on account of its changed
refraction of light from that of the rest of the stone, may be
detected ; or the Diamond is exposed to a great heat, and is then
thrown into water, when it vdll crumble to pieces should any
cracks exist within it The Diamond, although the hardest of
all known substance, may yet, with facility, be cloven with steel
tools, the blow being properly applied. The octahedrons are best
fitted for cleaving : they are generally, however, somewhat round-
ed, and in order to cleave them, those planes which are to be cloven,
are left bare, and the rest is coated with a composition of resin
and brick-^ust ; the bare plane is now rubbed with another sharp-
edged Diamond until a furrow is obtained, which will render the
planes suitable for applying the cleaving instrument, and this
operation is repeated with every plane. Diamonds that are not
fit for being cloven, are called by the Dutch, <^ divdsteene^ (devil-
stones). Large Diamonds, which are too precious to be exposed
to a dangerous cleavage, are sawed by means of a fine 9teel wire,
moistened with oil and Diamond-powder.
g6 TIW^TISi; OH C«MS.
J^tl^^wis ^v;^ tiff following descriptioo of the «^ of cuC^
<< 71^§ PVj^ c^ f>}i(iiog aqd poUaU^g tb^ Diamond ipi (wo-
fold:^^
" First, to divide the natural surfoce of the stone in a symmetri-
cal manner, by means of a number of highly-polished polygonal
planes, and thus to li>ring out to the best advantage the wonderful
refulgence of this beautiful gem ; and, secondly, by cutting out
such flaws as may happen to be near the surface, to remove those
Uemishes that m^rially detract from its beauty, and consequently
^< The renjipvej of toW9 is 9. matter of great importance : for,
owing to tbe form ia whi^l| the Diamond is cut, and its high
degree of refra^gibility, the pmallest. &ult is magnified, and be-
ipome^ obtrusively visible in eveiy &pet For this reason, also, it
13 by no means an e^isy lyiatter, at all times, to ascertain whether
4^ ^w i^ or is not superfii^ial ; and a person with a correct and
^eJl-pr^tised oye niay ofteA purchase, to great advantage, ^toniBs
i9rhip)i app^r tp be fls^wed (jilite through, but are, in fojct, op^y
fnjperficially blemished.
'^ T(ie fillet thing the artist has to do, whep a rough Diamond is
put into }^s bands, i^ to examine carefully in what direction the
iftopei m^y be ci;t, so as to afford the greatest breadth, or spread^
^ it ^ t^hi^ipally termed, after the flaws, if apy, shall have been
^en out. So great a stress is laid, by modem fieushion, on the
foiper^ci^ ^sxteat of a brilliant, t^t the old rules of proportioning
its 4i<^Pi^ct08 are now nearly obsolete: the best cutters have
eptirMy discarded the use of measures, and, in forming the fopets,
^^t wholly to s^n accurate and we)l-practised eye. The directic»i
l^eipg 4^ti^rmine4 on, the artist must be well aware whicl^ are tl^e
. hard points and .which the soft ones ; the fcnriner being those
solid angles of the original octahedron, which it is necessary to
cut directly across, and the latter those solid angles wh^ch are to
\fe obliquely divided. A degree of force which may be safely ap-
plied* &nd is eyen requisite in making a section through the former,
wii^ be very apit to flaw and tear up the laming when applied to
i}}^ Ifttte^r. On these accounts it probably is, that the fatiguing
l^d f y^n paipful process of performing this part of the business
^ by hand, is not yet suspcirceded by the use of n^qhipery.
TftBATISB ON OElfS. 37
'^Thiese prelimuiaiy matters being lettled, ibe IKamond is
embedded in a strong cement, fixed at the end of a stout sfmidle-
sdaped stick, about a foot long, with that portion only projecting,
(be remoYal of which is to fiirm the first facet The instrument
^n{4oyed for this purpose is anodier Diamond, fixed in a stick
similar tp the former, with one of the solid angles projeoting. In
order to collect the powder and shivers that are detached during
the process, the cutting is performed over a strong box, four or five
inches square, furnished with a folse button), perforated with
exceeisively minute holes, in order to sift, as it were^ the dust from
the shivers; ^nd also with two upright iron pegs, fixed on the sides,
fop* the workman to support and steady Ins fingers agaim^, while
with a short repeated stroke, somewhat between scratching and
cutting, he is 8{ditting ofi*, or more laboriously wearing away the
Diamond in that part where the facet is to be placed. This being
done, the cement is softened by warming it, and the position of
the Piamond is changed, in order to bring a fresh part under the
action of the cutting-diamond. When, in this slow and laborious
way, all the facets have been placed upon the sur£»ee of the
Dis^mond, the cutting is com[deted. The stone, if examined by a
moderate magnifier, now presents ragged, rough edges ; and a
brokei), foliated surftu^, with a glistening lustre on those ftieets
tbat are nearly in the direction of the natural laminsB, and on the
other fi^cets a more even sur&ce, but of $i dull opaque- grayish-
white colour.
'< The shape of many Diamonds is so irregular, that it is neces-
^y to remove pieces of considerable magnitude in order to bring
tbem to a form proper for cutting. Where the lines of these pro-
posed sections coincide with the natural lamellar structure of the
stonf^ the workman has recourse to the delicate, and perhaps some
what hai^rdous, operation of splitting the Difkraond, by which a
double advantage is obtained. In the first place, there is a great
saving of time ; and in the second place, the slices or shivers are
tbemadves sufficiently large to admit of being cut and polished.
The method of splitting is made a great mj^ery ; thus much,
however, may be mentioned, that when the direction in which the
sectioii is to be made has been determined on, it is marked by a
very fine ^i^e, cut by the point of another Diamond : the stone is
afterwards fii^ by strong cement in the prqier position, in a Mock
38 TREATISE ON GEMS.
of wood, and then, by the application of a due degree of force, the
section is effected.
'< The Diamond being thus, by the joint action of splitting and
cutting, brought to the required form, Uie next object is to polish the
fecets, and at the same time to redress any little inequaUties that
may have taken {dace in the cutting. The polishing-mill is an
extremely simple machine, consisting of a circular horizontal plate
of cast-iron, fourteen or fifteen inches in diameter, called a skivCf
suspended on a spindle, and capable of being put into rapid motion
by means of a larger wheel, five or six feet in diameter, and turned
by an assistant From the centre to the circumference of the iron
plate, are lines or shallow grooves, formed by rubbing it in that
direction with a fine grained gritstone : these grooves serve to retain
the mixture of oil and Diamond powder with which the plate is
charged. In order to keep the Diamond perfectly steady while the
polishing of each facet is going on, the following contrivance is had
recourse to : — ^A copper cup, called a dopp, about three-quarters of
an inch in depth and m width, and furnished with a stem about
four inches long of stout copper wire, is filled with plumbers' solder,
which also projects in a conical form beyond the rim of the cup :
in the apex of this cone, the solder being softened by heat, the
Diamond is imbedded with one of the fecets projecting. The stem
of the cup is now put into very powerful pincers, which screw up
with a nut and a wrench or lever, and thus hold it perfectly tight
The handles of the pincers (made of wood, and called tongs) are
broad, and terminate in two feet, about an inch high, so that when
laid horizontally, they are supported exactly as a pair of candle
snuffers are, the studs fixed to the handles of the snuffers represent-
ing the legs of the pincers, and the single stud near the point of the
snuffers representing the inverted copper cup holding the Diamond
is placed on the plate, the pincers resting on their legs on the wooden
bench or table that supports the plate, and pressing at the same
time against an upright iron peg ; the broad part of the pincers
between the legs and the Diamond, is then loaded with weights,
both to steady the machine, and to increase the pressure of the
Diamond against the skive. Matters being thus adjusted, a little
oil and Diamond powder is dropped on the plate, it is set in motion
at the rate of about two hundred revolutions in a minute, and the
process of grinding down, and at the same timeof polishing, is begun.
TREATISE oyi GEMB. 39
The Diamond is taken up and examined from time to time, and is
adjusted so as to give the facet its true form. The heat occasioned
by the friction is at all times pretty considerable, and when the
pincers are heavily laden, it occasionally increases to such a degree
as to soften the solder and displace the Diamond. This is a serious
accident) frequently occasioning a flaw in the Diamond, and always
tearing up the surface of the skive, so as to damage it very consi-
derably. There is room on the skive for three or four Diamonds
at the same time ; and, to give each its proper share of attention,
is as much as one person can well manage. The completion of a
single facet often occupies some hours."
The polish is often produced by rubbing the Diamond with a
cloth or bare hand. The form which the gems have to receive from
the lapidary varies according to the condition of the stones ; and
the skill of the artist consists in the right selection of a form which
shall correspond with the natural structure of the gems. A good
cut has the greatest influence on the lustre and beauty of gems ;
the colourless and limpid gems, for instance, require a different form
from those which have a play of colours. With a Diamond, the
form must correspond as much as possible with its natural or origi-
nal shape, in order to save the great trouble of grinding, and the
waste thereby produced. Transparent gems ought not to be cut
too thick ; the rays of light might otherwise be refracted too much,
or prevented from penetrating through them at all : in the first in-
stance, the lower fricets do not act in correspondence with the upper,
and the rays are much distributed before reaching the eye. Gems
of such description are called clotty. On the other hand, if the
gems are too thin, their beauty, elements, and general value are
likewise diminished. There is a definite proportion of thickness
to the breadth of colourless or limpid gems, whereas the cut of the
ccdoured gems depends upon the intensity of the colour.
§ XXXV. FORMS OF THE DIAMOND.
Diamonds were formerly cut according to their natural form, and
mostly in the planes of the octahedron. They were called then
point Diamonds (pierris de Nature, or pointes ingenues).
The following forms are now, more or less, adopted by the Dutch
and English Diamond cutters : —
40 TREATISE ON OEMS.
Ar The Brilliant. This eut displays to greatest adrantag^e the
lustre of the Diamond : it may be considered as obtained by two
truncated pyramids, united together by one common base, the
upper pymmid being much more deeply truncated than
><i the lower. It is formed — a. Of the croum, or that part
^f of the stone which remains visible after the stone b
mounted ; b, The collet, or lower part ; c, The girdle, or the
common base for the crown and edlet ; d. The tcAle, that plane
which is ibrmed by the truncaturc of the upper pyramid ; e, The
biselj that space which lies between the girdle and table ; and/.
The collet-side, that space between the girdle and collet. TIm
English lapidaries cut the girdle sharp, whereas the Dutch leave it
broad : the crown amounts to one-third and the collet to two-thirds
of the whde height of the Diamond ; the table amoimts to four--
ninths of the diameter of the brilliant, whereas the collet only needs
one^fifth of the size of the table. The table and collet are regulat
oiotagons, and the fecets occupied by the bisel are eight lozenge^
with twenty-four triangles^ and are called the star-facets ; the
&cets occupied by the coUetrside are four irregular pentagons^
alternating with as many irreguldr lozenges^ radiating from the
GoUet as a centre, and are bordered by sixteen trian-
gotar facets adjoining the girdle, and are genciraUy
called ih& pavilion of ero^ facets; Accoifding to the
number of facets, the brilliants receive their namee^
either of double or treble brilliant : the double brilliant
is sunounded by two rows of facets on the bisel, which
are triangular^ and meet each other ; the treUe bril-
liaat has fifty^eight planes^ fifty-six facets, table and
adlietj thirty-two facets of yfkkh are iti the bisel in three rows ; the
star and pstvilion facets are triangular, the intermediate ones afd
fimr-Mded, and on the ccdlet-side are twenty-four facets.
The English double brilfiant consists of twenty-four facetS) table
and collet, sixteen of which terminate in the form of a star in the
bisel.
BciUiondts^ or half-brilUants^ are those Diamonds, the spread of
wUsh is too great in proportion to theiu dq>th^ and the erowa ie
only cut like a brilliant^ but the coUet-«ide is wa&tiii^.
TREATISE ON GEMS. ' 41
Bf The Rose-Diamondj has but a crown, and no
collet ; it is formed of equilateral triangles, and consists
of two rows of three-sided facets ; those on the girdle
are pavilion, and the others star-fiicets. But there are
variations in the number of facets : the Dutch roses have eighteen
pavilion and six star-facets ; others have six pavilion and six star
fisusets, or twelve pavilion and six star-&cets ; and some, also have
twenty-four three-sided pavilion and twelve star-facets. The Rose
Diamond is only that Diamond, the proportion of whose breadth to
its depth is too much extended, and which would not, without much
loss, make a good brilliant. There are fragment Rose Diamonds,
which are very small, and Ear-drop Roses.
C, The Table-Diamondf is that stone which is
very flat, and of little depth, and which reflects but
little lustre : they have a table with four planes and
eight facets ; and, in order to make the best of their
lustre, they receive a brilliant cut.
D, The Bastard-Diamond, is that Diamond whose cut is
mixed up from the above forms.
There are a few more forms given to those Diamonds which ar^
found unfit for any of the above cuts, such as the Thick-Stones,
the Portrait Diamonds, the Senail Diamonds, which are, however,
all unfit for the above cuts.
J XXXVI. FORM OF GEMS.
The gem lapidary occupies himself not only with grinding the
common and rare gems, but also pastes, &c. : he uses Ukewise
wheels, but of different material from those for Diamonds. His
wheels are either of copper, df for very hard stones ; or of lead or
pewter for softer stones ; he has likewise polishing wheels. If any
wheel is too soft for very hard stones, he cuts furrows in it, which
are then filled out with rotten-stone or tin ashes ; or if very hard
stones, such as Sapphire, are to be ground, the Diamond powder is
used for the same : likewise tin wheels are used for hard stones ;
water, also oil of vitriol, are used for moistening the wheels. The
gems, in order to grind them or to give their facets, are likewise
cemented into a handle, at the end of which is a composition of
resin and brickdust. Particular attention is required in grinding
the coloured gems, as the greatest effect may be produced by their
p
42
TREATISE ON GEMS.
thickness ; pale-coloured gems require to be left tliicker than darker
ones ; on the other band, they ought not to be left too thick, as they
will appear too dark, and thereby lose their lustre. The same
proportion in the manner of cutting the crown and collet of the
coloured gems has to be observed as with the brilliant, namely, the
crown ought to be one-third, and the collet two-thirds in size of the
depth of the whole stone ; if the gem be of a pale colour, the collet
ought to be three-fourths of the size ; and if of a darker colour,
much less : the table of those coloured gems which require to be
heightened, ought to be waved somewhat, whereas it ought to be
even in darker gems. The forms of the coloured gems received
in cutting, resemble, in many instances, those of the Diamond ;
but the following are the additional ones they receive, according to
the nature of the shape and colour of the stone : —
Aj The Step or PavUion cut. The planes,
which are long and small, decrease towards the
table and collet, and terminate in steps ; the crown
has usually two, and the collet four or five facets on
each side ; the form of the stones may be of four,
six, eight, or twelve sides, or may be long or round. This cut is
particularly applicable to coloured gems, as it reflects the light in a
high degree, by which the play of colour is much raised ; and it is
at all events to be preferred in the collet of coloured gems, even to
those brilliants in pavilion : the crown may be of any form
whatever.
jB, The Mixed facet cut, is a compound of
brilliant and pavilion cuts, the first being on the
crown ; it is a very ftivourite cut for coloured
gems, and contributes much in raising the
lustre.
C, The Elongated Brilliant facet cutj
which, if the brilliant facets are on the crown
elongated, and the collet has a pavilion cut, is
very appropriate to long and thin stones.
sealstones.
TREATISE ON OEMS. 43
Dy The Table cut, having either an uneven or
conchoidal table, with one or two rows of fecets, in
a circular form, around it ^ a very useful form for
E, The Double facet cut, the crown having two
rows of &cets, and the collet the pavilion form ; this
cut is well adapted to such stones as require the
concealment of any faults, flaws, or fissures.
F, The Cabochan cut, is either flat, convex, or double-convex,
that is, arched ; it may be on both sides, or only on
one. This cut is particularly applicable for semi-
transparent gems, or those which display their peculiar colours :
such as the Opal, Moonstone, &c. ; or collect the light in a small
space, on one or several points, according to the convexity they have
received. The Cabochon cut may have one, two,
or more rows of fiicets ; and opaque stones receive
with advantage the fecets over the whole surfoce.
Garnets, for instance, which are generaDy of a dark
colour, are cut en c(zbochon, the lower plane excavated in a circular
form, and the upper plane all around with facets. Other gems, the
interior faults of which cannot be concealed, may be improved by
this cut, giving them more transparency, vividness of colour, and
a greater degree of fire.
A judicious choice of the form in which any particular gem shall
be cut, depends on the skill and discrimination of the artist
§ XXXVII. COMMON LAPIDARY.
Such common precious stones as are suitable to be cut for snuff-
boxes, rings, grinding mortars, seals, and ear-rings, are wrought by
the common lapidary, by means of copper or iron wheels revolving
vertically. The tools are generally of iron, and sometimes brass ;
some are flat like chisels, gouges, ferrules, and some others have
conicular heads. The polish is given with rotten stone, on a tin
plate ; or with crocus martis, on a wooden plate covered with felt
The cuts applied by the workman are either even, cup-shell form,
excavated, elevated, or quite simple : facets are not used by him.
Mr. Mawe describes a lapidary's apparatus, fit for polishing min-
erals, shells^ &c., and which may be placed in a parlour, where
every operation of polishing, on a scale sufficiently^ large, may be
44 TREATISE ON GEMS.
effected, and pebbles may be slit of three or four inches diameter :
it consists of the fcdbwing mills : —
1st A lead mill, or wheel, to be used with emery and water, for
grinding down substances preparatory to polishing.
2d. A pewter mill, to be used with rottenstone a little wet, for
polishing.
3d. Tin plate, properly prepared, the edge of which is to be used
with Diamond powder, to slit or cut hard stones asunder.
4th. Wood mills, covered with leather, &c. for polishing marble,
alabaster, shells, or other soft substances.
§ XXXVin. ENGRAVING.
The value of many precious stones is increased by engraving
them. The common gems have, for several centuries, been used
in heraldry. In Italy, Germany, and England, we find the coat
of arms of distinguished or noble families engraved on stone. The
machine used for such purposes is like that of the glass cutters,
with this difference, that finer and harder instruments, and some-
times Diamond splinters, are required for this work. Before the
stone can be cut or engraved, its surface, after having received the
proper shape and form required, is rubbed with emery, glass, or
leaden wheels : the artist now makes his drawing with a brass pin,
and executes it afterwards with his tools. On hard stones he uses
Diamond powder ; on soft, emery and oil
The engraving of armorial bearings, single figures, devices, &c.
on any gem, is performed by means of a small iron wheel, the ends
of the axis of which are received within two pieces of iron in a
perpendicular position, that may or may not be closed as the opera-
tion requires ; the tools are fixed to one end of the axis, and screwed
firm ; the stone to be engraved is then held to the tool, the wheel
set in motion by the foot, and the figure or device gradually formed.
Difficult works are executed after models of plaster of Paris, of
clay, or other substances ; the polish is afterward given on wheels,
provided with brushes or with rotten-stone. The semi-transparent
and opaque stones are more used for engraving than the transpa-
rent gems, because the drawing will not show distinctly through
them, on account of the great refraction of light ; the same is the
case with iridescent or shining stones. The engravings are gene-
rally bas-relief or raised ; those having layers are mostly preferred
TREATISE ON GEMS. 4^
for cameos : for instance, the Onyx, Sardonyx, and Chalcedony ;
also. Wood-opal, which is constantly exported from Germany for
the Italian artists in Rome.
§ XXXIX. SAWING AND DRILLING GEMS.
Gems and precious stones often require to be sawed in dilSferent
directions, which operation is performed on a machine like that of
a lapidary, with the exception of a polishing plate, for which is
substituted a cutting plate having sharp ends, or by fastening the
stone on a stand, and moving continually a fine iron or copper
wire stretched in a bow, which is moistened with emery and oil.
Care has, however, to be taken not to let the stone grow too hot, as
the heat may crack or make it spotty. The Chinese use strings
spun over in preference to the wire, they having the advantage of
keeping the emery sticking to them, and of accelerating thereby
the operation. For drilling gems or other precious stones, a Dia-
mond set in steel is made use of to move to and fro by a bow, or
the common engraving machine, the drilling instrument of which
consists of an iron point, to which is fastened a Diamond splinter,
which is pressed upon the stone while it is revolving upon the plate.
§ XL. GRINDING AND POLISHING MATERIALS.
The materials for grinding and polishing vary according to the
hardness of the gem : the Diamond-powder is obtained by grinding
real Diamonds, which are unfit for use, with each other in a hollow
cylinder of cast iron, in which another one exactly similar is used
for the most costly and the hardest gems. Corundum, Sapphire,
Topaz-powder, and emery-powder, are commonly used for grinding
and polishing the Diamond. It is well to remark that emery is
often adulterated by a mixture of quartz and oxide of iron, or by
garnet or iron-powder. Emery fit for the use intended, requires to
be properly pulverized and levigated. According to Hawkins, the
following method is pursued in England: — The emery is pul-
verized in an iron mortar and passed through different sieves, one
finer than the other : the first is levigated with oil, which keeps it
in better suspension above water ; according to the time in which
the powder settles, the difierent numbers are thus obtained.
For polishing the difierent precious stones, hard and soft gems,
the Diamond powder and emery are mostly used. Rotten-stone^
46 TREATISE ON GEMS.
tin-ashes, pumice-stone, oxide of iron, English jewellers'-red, are all
used in their finest pulverized state. A great deal depends upon
the polish which a gem has received ; all its other superior qualities
being thereby called forth.
§ XLI. RAISING THE COLOUR OF GEMS.
Since colour is one of those characters which is the most tempt-
ing in the sale of gems and jewellery, all means are employed for
heightening the same, and covering any real defect 'Foil of small
thin metallic substances, coloured or uncoloured, either of fine silver
or copper, is placed under the gem in the back of the mounting,
which heightens the colour and lustre, particularly of the transpa^
rent gems. Almost all gems were formerly set in black coloured
backs, composed of burnt ivory-black and gum mastic, but are now
mostly set a jour ^ which is, leaving the lower part of the stone un-
covered in setting, and only mounting around the girdle, an old
method, and very applicable to perfect stones, where no defects
require concealment.
Foiling materially heightens the lustre of gems. The Rose
Diamond always requires it on account of its flat form. There
are many gems which would not produce any effect without the
foil. It is therefore used whenever a pale or impure colour is to be
raised, or when the gems are to be protected against dust or moist-
ure in order to produce a uniform shade of colour ; the foil forms
then a suitable application.
The colouring of the foil is generally performed by the jewellers*
Isinglass, first dissolved in water and afterwards boiled in spirits^of
wine, and then strained, is the mass or body to which the colours
are afterwards added, which are also soluble in water.
For producing a red colour, the best material is carmine,
" Blue, Litmus,
« YeUow, Saffron.
To produce the different shades and varieties of colour, the above
are mixed in different proportions with each other. Very clear
stones, such as Chrysoprase, Carneleon, etc., are sometimes painted
on the back. The Paris jewellers are very skilful in painting stones
of inferior value so as deceive even professional men ; it is for this
reason that gems when set, ought not to be purchased ; the valuable
gems which have a foil on their back are mostly set in such a man-
TREATISE ON GEMS. 47
ner that they may be examined without the same. Foiled gems
may likewise be distinguished by holding the table of the set gem
on the nail of the thumb and observing the passage of the
light through the crown.
In the Easti rubies are never set with foil, but a cavity is made
from below and filled with finely polished gold, which raises its
lustre remarkably.
Fissures, flaws, or veins, in the interior of gems, are mostly con-
cealed by the foil, and when near the girdle, are covered by the
mounting.
The defects of stones are sometimes concealed by colouring the
case with mastic and ivory-black, and according to circumstances
leaving blank the spot of the faulty stone, or covering only the
spot, so as to produce a uniform colour. Another and not unusual
method of concealing fissures, flaws, or other faults, is to cut those
stones having many faults, the momentary detection being thereby
prevent/ed from the play of the refiracting light and the lustre.
The colour of many g^ms is raised by fire, which acts in a
peculiar manner on them ; thus the Brazilian Topaz assumes
a very fine, pale red colour by burning ; the process of affecting
this colouring is very simple, viz : after wrapping the Topaz in a
sponge, ignite the same and keep it burning until consumed.
The Zircon sometimes assumes a better colour after having
been subjected to a high degree of heat Amethysts having dark
qpots, may be calcined for a short time in a crucible containing
sand and iron filings, under which process they mostly lose those
&ulls ; but if exposed to an excess of heat, they will loose their
colour altogether and become as white as quartz. The Oriental
Cameleon assumes, after burning, a fine colour, and in Hindostan
those carneleons which are found detatched in the mines, are cut
up and burnt on the spot. Yery fine cracks are sometimes
produced in mounting stones, which may be repaired and con-
cealed successfully by means of ^riia juice. When stones are
broken by the same operation, they may be cemented by gum
mastic.
J XLII. SETTING OF OEMS.
The genui.are generally festened or set at the girdle in a box or
rim of metal : limpid and fiiultless gems are sdways set i yniXy
48 TREATISE ON OEMS.
(i. e.) without backs, since tbey appear then to the best advantage,
and if the gem is intended to display its full size and colour, the
a jour setting is only fastened by small shanks or claws. The
good setting of a gem very much increases its value and beauty.
The material for mounting the limpid gems is silver, which dis-
plays them to more advantage than gold. In order to increase
the colour or lustre of large gems, they are often surrounded by
smaller gems, such as small Roses, Rubies, Emeralds, Garnets,
Turquoise, &c.
The jewellers wax used for mounting the gems, is made of
three parts rosin, one part bees-wax, and four parts fine brick-dust.
§ XLIIL CLEANING THE GEMS.
The following composition I have found to be the best for
thoroughly cleaning gems, particularly when set : — Take one part
flour of sulphur, and two parts of rotten-stone or bone-ashes,
which when mixed is used by rubbing it on a piece of buck-skiD
and with that and a stiff hair brush alternately rubbing the gems,
finishing with a softer skin or cloth to remove the dust.
§ XLIV. IMITATIONS OF GEMS.
Pliny mentions the imitation of jewels by glass fluxes, and it is
sufiiciently proved that the ancients were far advanced in this art.
The Egyptian mummies were provided with glass-buttons of green
and blue colour, and during the reign of the Roman empire,
coloured giftss was very general ; and we find antique cameos
carved in various coloured glass, representing the Onjrx, likewise
coloured glass cemented with real Onyx, but they never attained
such perfection in their art as to set at defiance the skill of the
artist and jeweller to distinguish between the genuine and spurious
ones. The imitation of gems may be divided into three classes: — *
A, The Pastes, The basis of these imitations is a fine, pure,
and white glass composition, called strass, after its inventor,
Strass of Strasburgh, in the seventeenth century, who first con-
ceived the importance of imitating the real gems as respects their
hardness, specific gravity, and refraction of light. He accomplish-
ed the task so far that in many instances, either all three, or one
or the other of his objects were attained. The strass is composed
of silex, (quartz, flint, or pure sand,) potash, borax, red-lead, and
TBKA.TISE30N GEMS 49
sometimes arsenic. To tliree hundred parts of sflex add nin^y-
six parts potash, twenty-seven parts borax (prepared from the
Boracic acid,) and five hundred and fourteen parts of white-lead,
and one part arsenic ; or according to another method, mix seven
ounces and twenty-four grains of quarts with ten ounces and
seven and a half drachms red-lead, three ounces and six drachms
pure pearlashes, three twenty-seven-thirtieth drachms horax, and
twelve grains arsenic ; the mixture is put into a covered hessian
crucible and kept at a great heat in a pottery furnace for twenty-
four hours. The longer the mass is kept in a fluid state, the
harder and clearer it will be when turned out and cooled. This
discoloured strass is used by the lapidaries for imitating the
Diamond, rock-crystal, and white Topaz.
For imitating the coloured gems, various colouring ingredients
are employed. To obtain that intensity of cdour approaching
nearest to the original gem, it is experience alone which can guide
the manu&cturer. In order to imitate the uniform and intense
colours, the strass colouring ingredients are to be of the finest
powder, and very intimately mixed ; the mass is then to be
exposed to a very great heat, and in that state left for nearly thirty
hours, so that the cooUng may be gradual. Numerous establish-
ments in Germany and France, are now engaged in the manufac-
ture of the strass and cdoured pastes, each of which possesses
secrets acquired by experience, for producing these articles in the
greatest perfection. I will now mention a few imitali^uis of some
of the most predous gems, and shall in the second part of this
essay always allude to those which are imitated, with the receipts
for producing such imitations, obtained from the best sources and
my own experience ; viz : —
A, Artificial Topaz. Take of perfectly white Strass one
ounce and six drachms, glass of Antimony thirty-seven grains,
and cassius pur{de one grain ; or add to six ounces of strass, half
a drachm of crocus martis.
B, Artificial Ruby, This may be obtained from the preceeding
mixtuce for the Topaz by the addition of eight parts more of
8tras8, and left for thirty hours in fusion ; when taken out and
fiised before the blow-pipe, it yields a moBt beautiful Oriental
Ruby. Five ounces strass and one drachm oxide of manganese
may be eaqplogml for the same purpose, bii^ will not make ao fine
G
60 TREATISE ON OEMS.
a Ruby. Or by calcining ammoniacal alum with chromate of
potash and lampblack, which forms the composition of
97 parts alumine,
1 " oxide of Chrome,
2 " silica and Lime.
C, Artificial Emerald. To one pound of strass, add one
drachm of verdigris and fifteen grains crocus martis.
D, Artificial Sapphire. Add to eight ounces of strass, fifty-
two grains pure oxide of cobalt
E, Artificial Amethyst. To eight ounces of strass, add thirty
grains oxide of manganese, twenty-four grains oxide of cobalt,
and forty grains cassius purple ; or to one pound of strass, twenty
grains oxide manganese, and one grain oxide of cobalt.
F, Artificial Aquamarine. To six ounces of strass, add
twenty-four grains glass of antimony, and one and a half grains
oxide of cobalt.
C, Artificial Syrian Garnet. To one thousand grains of
strass, add five hundred grains glass of antimony, four grains
cassius purple, and four grains oxide of manganese.
It will now be necessary to show the distinguishing characters
between the real and artificial gems, as they so closely resemble
each other that a superficial inspection will not always enable the
examiner to discriminate between them ; they are as fdlows : —
1. The hardness ; which may be tested on the grinding
machine; with fine quartz sand it will immediately attack the
pastes, or by scratching with a real onjrx, to which the pastes will
immediately jield.
2. The small air bubbles in the pastes, may more or less be
detected with a good magnifying glass.
3. The cold touch will never remain for any length of time
on the pastes as it will on the real gem.
4. The breath remains much longer on the pastes, on account
of their bad conducting power, than on real gems. The specific
gravity and electricity, may Ukewise indicate the difference, — but
I never depended on them alone, and I will mention that I once
examined the specific gravity of an artificial Topaz which fully
corresponded with that of a Brazilian Topaz. The electricity
will indicate the difierence between real and artificial gems by the
length of its continuence ; for real gems retain, after being rubbed,
TREATISE ON GEMS. 51
their electricity for from six to thirty-two hours, whereas, the
artificial ones only retain it from forty to sixty minutes.
B, The Doublets, This mode of imitating the real gems is
called the doubling, when a quartz, cut and polished, is cemented
by means of gum mastic to another coloured paste, whereby the
whole stone assumes the colour of the lower paste. If a real gem
is employed instead of the quartz, as the surface and the quartz
or paste is cemented below, it is called half doubling. This
adulteration is carried on to a very great extent in the East Indies,
where they paste any thin gem to a paste corresponding in colour.
The concave doubling is effected by excavating the inside of a
quartz or paste. The cavity being filled with a coloured fluid,
and the other part afterwards cemented on it, will, when well
executed, present so uniform a colour that it is diflicult even for a
judge to detect the deception. The surest method of detection is
to put the specimen in question in hot water or alcohol, by which,
the gum mastic will be dissolved. When set, the only way of
finding out the adulteration, is to put it reversly on the nail of the
thumb, when the false refraction of light or the rainbow colours
will, with certainty, determine their identity.
C, The Burning. This mode of adulterating the real gems,
is performed by colouring cut and polished quartz specimens and
throwing them into a solution of permanent pigments, such as a
solution of indigo, decoction of cochineal, solution of ammoniacal
copper ; the small cavities produced by the heat will absorb the
fluids. The Topaz is burnt by itself, with or without the absorp-
tion of a pigment, as also the Spinell, and the Quartz ; Chalce-
dony is, however, frequently burnt to imitate the Onyx, and to
engrave thereon the Cameos and the Intaglios.
It may be remarked, however, that since the introduction of
coloured pastes, very few adulterations of this kind are now
practised, and we see but rarely such doublets and burnt stones.
J XLV. PRICE OF AND TRADE IN GEMS.
It is difficult to determine the price of gems without reflecting
upon all the circumstances relating to them, such as beauty and
uniformity, the play, the lustre, and the vivacity of the colours, as
also on the perfection of the cut, the polish, the rare locality, the
size of the individual gems. It depends upon the trade of the
52 TREATISE OH GEBiS.
yarious countries whence they come, and are sent to the staple,
and what quantity of such valuable gems may be had at one
time at any of the great cities : so we find that Diamonds were
often sold at a much less price in Lcmdofi and Paris than in Brazil.
The fuincipal trade, however, is as yet carried on in Brazil and
the East Indies, although it is in no comparison so prosperous as in
former years. The gems are sold by weight, such as carat and
grain. One carat is equal to four grains, and forty-four carats are
equal to one ounce. The name carat is derived from the word
Kuara, the coral tree, (Rrythrina,) the red pods of which, when
dry, were formerly used for weighing gold dust, and each of them
weighs four grains, which is equal to one carat
5 XLV. GEMS FOR OPTICAL PURPOSES.
A few years ago, Messrs. Trecourt and Oberhauser laid before
the Parisian Academy lenses of diamond, sapphire, and ruby,
which were used in connection with glass lenses in microscope»;
they were of nine-tenths millimetre, in diameter. The diamond
lens magnified two hundred and ten times, that of sapphire two
hundred and fifty-five times, and that of ruby two hundred and
thirty-five times, in a linear extension.
A letter was lately published from Sir David Brewster, on a
curious optical phenomenon that had occurred in the constructioa
of diagonal lens. The Diamond, previous to working, had all the
appearance of internal brilliancy; but, after being polished, it
presented a series of stratified shades, which rendered it useless for
the required purpose. It afterward appeared that lapidaries were
acquainted with this appearance, which rendered them extremely
unwilling to take the risk on themselves, of cutting up Diamonds
for optical purposes. On a minute examination of this phenome-
non, it appeared that these different shades occurred in regular
strata, each section being about the one-hundredth part of an
inch, and each stratum having a different focus, and being of a
different degree of hardness and specific gravity. The inferences
drawn from the above facts were : — ^that the Diamond was a
vegdMe substance, and that its parts must have been held in
solution and sul^ted to different degrees of pressure at different
stages of existence. If, on the contrary, as it has been generally
believed, subject to the laws of crystaUisataon, its crystals mtost
necessaiUy have been homogeneous.
TREATISE ON GEMS.
PART II.
CONSIDERATION OF THE INDIVIDUAL GEMS.
L DUMOND.
We will now proceed to the consideration of the different gems,
which have mostly been arranged according to their hardness.
Diamond : Diamant (German), Adamant (of the ancients),
Almas (Oriental), Diamant (French). The name Diamond is
derived from the Greek, Adamas, meaning invincible, and referring
to the hardness of the gem. The Syrians are said to have first
known the Diamond, and it was in early ages the subject of trade
to the people of the East The Carthagenians are said to have
carried on their trade with the Etrurians, who procured Diamonds
from the interior of Africa. Pliny mentions six species of Diamonds,
among which, however, the Indian are to be considered the true,
in contradistinction to the quartz crystals, which were likewise
called Diamonds in those times. The Diamond was highly
esteemed, and many medicinal virtues were attributed to them,
particularly against mania, and as an antidote for poisons ; and
the Diamond was worn in the rough state. The art of cutting it
with its own powder was discovered in 1476, by Lewis Van Berghen.
In the beginning, they cut it in the table form, with one row of
&cete on the sur&ce : afterwards, in 1520, they made use of the
rhomb cut ; and the form of brilliants was invented in the reign
of Louis XII. The Cardinal Mazarin was the first who had
Diamonds polished in this form, some of which yet belong to the
crown of France. For a long time philosophers vainly speculated
as to the nature of the Diamond; first it was considered as a min-
eral, consisting of silica ; but Newton was the earliest (1675) who
64 TREATISE ON GEMS.
expressed himself as to the constitution of Diamonds, Bfe judged
from the great refraction of light, that it must be a combustible -
body ; and a series of experiments with it, tested afterwards by
different naturalists, proved the same to be pure carbon. The first
trial was made in 1694, by the members of the Academy at Flo-
rence, by whom Diamonds were volatilized within the focus of a
mirror ; Bergman first classified the Diamond among combustible
bodies, and mentions having cut the head of the gems off.
Yarious views existed in regard to the origin of the Diamond :
Bome considered it as a secretion of a vegetable substance ; others
as originating from volcanic or plutonic. revolution. The Indians
beUeve Diamonds are continually regenerating and growing to this .
date ; and the inhabitants of Pharrah, in Hindostan, afiirm that
the quantity of Diamonds by no means decreases, but on the con-
trary, the soil will yield a new supply fifteen or twenty years from
the time it was exhausted.
Numerous experiments have been instituted to produce an arti-
ficial Diamond from several substances which contain carbon, and
by the application of a high degree of heat Dr. Hare, in Phila-
delphia, succeeded in melting down mahogany charcoal so as to
produce a metallic appearance, by his deflagrator. Professor Silli-
man likewise made similar experiments with plumbago, which
produced small globules, some of which were so transparent that .
they could not be distinguished from the genuine Diamond. Pro^
fessor Yanuxem, who examined the globules obtained from frised
chaFcoaly found them to contain iron and carbon, which led him
to the conclusion that the charcoal had not undergone a real fusion.
Cagniard de Latoor pretended to have discovered the ingredients
for imitating Diamonds of some size ; but Thenard proved those
small crystals of the appearance of Diamonds to be some silicates
of peculiar composition, which, according to Arago, polarized the
light in a different angle from that of Diamonds. All speculative
experiments to imitate this most precious gem by the various com-
pounds of carbon, have hitherto proved abortive.
The'Diamond is found crystalized mostly in the form of an
octahedron, (composed of two four-sided p3nramids, united by their
bases) or rhombic dodecahedon, rarely of a cube ; but the planes
of the angles are often rounded or bevilled. The fcliated passages
are distinctly parallel to the ftuses of the octahedron, in which
TREATISE ON GEMS. 66
directioQ tbey may always be split. The fracture is conchoidal ;
surfece smooth, often rough or striped, and sometimes covered with
a scaly crust ; it is transparent, also semi-transparent ; of an ex-
ceedingly Yivid lustr^ called the Diamond or adamantine lustre ;
. and when polished of splendid fire ; it is limpid, and likewise pass-
ing into the greatest variety of shadings from white and gray,
sometimes from yellow, green- and brown, but more rarely tinged
with orange, red, blue or black.
The Diamond being the hardest of all substances, yields to no
file ; its streak powder is white or grayish ; it becomes phosphores-
cent by the rays of the sun, and electric by rubbing, which property
it retains for half an hour ; ite specific gravity is S.S-^-S.G ; it does
not alter before the blowpipe; it bums, however, at ^ high degree
of heat,p and in atmospheric air with a bluish fiame ; its touch is
very cold ; it consists of carhop. The Diamond bears the same
name in trade, but is changed according to its cut : the blackish
and brownish Diainonds are called the Savoy Diamonds (Diamand
Savayards.) The cniginal bed of the Diamond is not yet known,
and on this point Opinbns are much divided : in the East Indies
we find it in a conglomorate of sandstone, consisting of quartz
grains, and disintegrated by the ferruginous sand ; and in the
mountain chain Ralla-Malla, in Hindostan, between 05° and 98^
E. L. Some of the celebrated Diamond mines consist of a breccia
from argillaceous slate, quartz, lime and sandstone ; the boulders
and the sand of deserts and rivers ]/ieId Diamonds mostly rounded
or in a granular form. The richest Diamond mines are those of
Roalcorda, at the junction of the rivers Bimah and Ristna ; Gol-
. conda, along the shore of the Pennar, Sumbhulpra and Biindelke^
Bed, in the neighbourhood of Pannah, where one thousand
labourers are kept employed. Visapur, Hydrabad, (fee, on the
island of Borneo, yield likewise Diamonds ; apd, according to
Jameson, Diamonds were foimd in the Indies in the coal for-
mation.
In Brazil, they were discovered in 1728, by chance, having been
always thrown aside with the flint and other refuse of the washings
of gold, until an inhabitant, who had some knowledge of rough
Diamonds, collected a large number, and carried them to Portugal,
and acquired by their sale a great folrtune. Another, who was
informed of ijOQ operations of the firsti shared an equally ^cxvl
66 TREATISE ON GEMS.
fortune. The government's attention was drawn to the matter, and
it was declared in 1730, that all Diamonds found there belonged to
the crown.
Diamonds are found in the talcoee chlorite schist, and in a
breccia, consisting of ferruginous clay, quartz pebbles, sand, and
oxide of iron fragments ; and also in a secondary bed, accompanied
by gold, platina, topaz, beryl, chrysoberyl, or tourmaline. They
are found particularly in the valley of Sejues, along the rivers
Jequetinhonha and Pardo, which run into the Diamond district ;
these carry most Diamonds by. The dykes and brooks of the
district contain more or less rich Diamonds, which are found there
in recent and older beds. Beyond the Diamond district, the Dia-
mond is likewise found in the province of Minas Geraes on the
Serro de St. Antonio, in the Serro Frio and in the rivers Aboite,
Andaja, da Saneno, da Prata, and several other places.
In Russia, the first Diamond was discovered in July, 1829, by
Humboldt and Rose, when on their journey to Siberia, on the west
side of the Uralian mountains, in the gold washing establishments
of Krestowosdwisheaski, belonging to Count Schuwalow. The
locality, in connection with the other circumstances of the place
where the Diamond was found, bears a striking resemblance to the
Diamond district of Brazil. The predominating rock of the spot
on the Uralian mountains is a quartzose chlorite, talcose schist (ita
columnit) with an admixture of iron pyrites and mica, wherein
we find beds of red oxide of iron, talcoee schist, limestone and do-
lomite. In the valley of Poludenka and Aedephskoi the Diamonds
are found among the debris of the mountains, accompanied by
quartz, itacolumnit, brown hematite, talcose slate, dolomite, chal-
cedony, anatase, gold and platina ; it is not yet decided to what
formation this rock originally belongs. The production of the
Diamond is two-fold ; either they are dug out from the earth, or
they are collected in the sand of rivers. If by the latter way, they
are more or less rounded, wedged and rubbed off: whereas the
former appear coated with an earthy, pale gray, yellow or rose-red,
rarely with a blue or green crust Many valuable mines have been
relinquished in the East Indies since the discovery of Diamonds in
Brazil. The locality of the finest Diamonds is at present in the
neighbourhood of Sumbhulpore. Two tribes, called the Thata
and Tora, living in sixteen villages, occupy themselves particularly
TREATISE ON GEMS. 67
with searching for Diamonds, beginning in the month of Novem-
ber, and continuing until the commencement of the rainy season,
more especially in the bed of the Mahanudi on its left shore, where
some other small rivers, Maund, Reloo, Eeb, &c. empty into it.
Four or five hundred individuals, consisting of men, women and
children, are examining continually all the spots of the river from
Cauderpoor to Longpoor, a distance of about one hundred and
twenty miles, till the stream is impeded by the rocks ; and likewise
all excavations or other cavities of the beds where any alluvial
deposites may be traced. All their implements consist of a pickaxe^
{ankova), a board five feet in length, excavated three inches in the
middle, but provided with its border (daer), and a smaller similar
implement, called by them kootla, both of the shape of a shovel.
The process is very simple : they first dig the earth with the axe,
and let it accumulate in heaps along the shore : the women after-
wards take it on their large shovels, and allow the water to run
over the earth ; they then pick the flints and coarse gravel out of
it, and bring the residue on the smaller shovels, spreading it out,
and examining it very carefully, separating from it the Diamonds
and grains of gold. Another method pursued in the East Indies
is to surround a small plain where the Diamonds are expected to
be found, with a wall two feet high, under which water is per-
mitted to run by several openings ; after having thrown a good
deal of earth within the wall, and the water has been allowed to
pass through two or three times, the larger stones are picked out,
the residue dried, and the Diamonds selected as before.
The washing establishments of the Diamond in Brazil, parti-
cularly in the celelM-ated district Tejuco, on the Rio San Francisco
and its adjoining smaller rivers, are conducted in the following
manner :r—
-la order to get at the bottom, or soil of the river, means are
uivd for laading the water at a certain spot into a different direction,
and then -that part of the bed of the river is allowed to dry out,
and the sediment found, consisting of a conglomerate of quaitz
pebbles, kept together by oxide of iron, is brought to one place for
washing it out It is a large bench of triangular form, so as to
keep from twenty to thirty negroes busy : in the middle of this
bench is abutter, with which is connected a trough, inclined some-
what, in ocder that the water may run down voluntarily, but so
H
gg UlEAtlSE pN OEMS.
^at it may be stopped by putting loam at the end ; and another
^tter with a trough is joined further down. The negro who has
tM>lleGted in the dry season a large quantity of the sediment, is
occupied in the rainy season in putting from fifteen to eighteen
pounds at a time in the trough, spreading it there, and allowing so
much water to run over it, until it runs off quite clear from the
lower trough, but at the same time keeping the trough continually
moving. He begins then to pick out the larger stones from the
^earthy part, and then the smaller, until he comes to grains, fully
'suitable to detect the smallest particles, which he examines with
the greatest care, on account of the Diamonds. As soon as a negro
has found one, he must make it known by clapping his hands, and
the surveyor, who is seated on an elevated chair, so that he can
oversee the work, takes and deposits it in a dish filled with water,
into which all those found during the day are collected. They are
then delivered over to the superintendant, who counts and weighs
them, and enters the result, with other particulars, in a book kept
for that purpose : he keeps them in a bag until he delivers them^
which he do6s twice a week, to the government at Tejuco.
Every superintendant has to live in the neighbourhood of the
iprincipal washing establishments, which were formerly leased for
a certain sum by the government ; but the impositions practised
rVere so great, that she took the superintendance upon her own
account in 1772, and has guarded the Diamond districts along
their lines by strong sentinels, who will not allow strangers to pass
through without the permission of the general superintendant ; and
even the inhabitants, wh^m crossing the line of the Diamond dis-
tricts, have to procure written permissions from the above authority j
and every body must, on leaving the district, submit, without any
dispensation, to a personal and strict examination and search by
the soldiers ; foot passengers are always arrested by sentinels and
spies continually on the alert. St. Antonio de Tejuco, forty leagues
from YillaRica, is the capital of the Diamond district, and the seat
of the superintendance of the Junta Diamontina, consisting besides
of a confiskal, two cashiers, one inspector-general and a book^
keeper. All the procured Diamonds are delivered up yearly to the
government at Rio Janeiro.
From four to five thousand negroes were engaged in the years
1772 to 1776.; in the year 1818 hut one thousand : among them
TREATISES ON GEMS. 69
w^re the feitores or surveyors, one hundred in number, in the latter
year ; likewise ten superintendants, whose business it is to conduct
the mining department and the collection of the Diamonds.
In order to encourage the negroes, presents of tobacco, cloth, &c^
are awarded, according to the price a( the Diamonds which they
find ; the one who finds, for instance, an Eighth (17 carats and 2
grains) receives his entire liberty; they are severely punished for
any offence, and if repeated are not allowed to be at this work^
Notwithstanding the most rigorous regulations and the most watch-^
fill attention of all the ofiicers, the firauds in stolen Diamonds are
very considerable ; and it is estimated that the smuggling amounts
to one-third of the whole income. The smugglers, who are run-
away slaves, examine the most remote parts of the district, or steal
the Diamonds at night from the working establishments ; others,,
again, who understand it, will take the stolen Diamonds from the
negroes, and devise means of escaping with them, either in the
soles of their boots, or in hollow canes, &c. ; and it is a remarkable
fact, that all Diamonds obtained firom the smugglers are invariably
larger and more beautiful than those which are brought into market
by the government. The thieves practice all manner of tricks and
impositions, even in the presence of the surveyors : for instance^
they conceal the good Diamonds, during the washing hours, be-
tween the fingers, the toes, in the ears, in the mouth or in the hair :
they also throw them away with other stones, in order to pick tben^
up in the night ; they often even swallow them.
The soldier who arrests any smuggler, receives a reward ; the
property of the latter is confiscated, and he is sent to Angola as
a prisoner, for upwards of ten years.
The pure transparent Diamond, which is cut in the different
forms already mentioned, loses generally one-third to one half of ita
original weight by this operation.
In purchasing rough Diamonds, every precaution ought to be
used to prevent getting false Diamonds instead of real ones, and
fiiulty ones instead of pure Diamonds. The ofiicers of the Junta
Diamontina test the rough stones by holding them whilst rubbing
together, cloee to the ear, and listening to the tune produced, whicl^
gives them ample satisfaction of their being genuine, as it is only
to be observed in real Diamonds. It requires however, considerable
practice to dislinguish them with accuracy by this test. Strangers
60 TREATISE ON GEMS.
particularly, are imposed upon by the negroes in Brazil, by pnr^
chasing from them gems cut and polished with the fecets, resemb*
ling those of the Diamond ; and although any one acquainted with
the Diamond will soon detect the imposition by the want of specific
weight, the peculiar lustre, fire and hardness, he requires to be on
his guard. If, however, the Diamond is ascertained to be genuine,
we have to examine particularly its purity, colour, form and size,
these being the quaUties by which the price of a rough Diamond
is to be determined.
It requires considerable experience to determine firom a rough
Diamond whether any of its faults are at the surfece or in the in*
terior, whereby often the Diamond, in removing all its feults, may
be diminished to half its size. We often, however, judge the rough
stones by their colour ; those turning towards the green colour are
considered to be the best ; those of a reddish colour to be good
stones ; the black colour indicates a hard stone ; and we judge a
yellowish or gra3ash colour as making bad Diamonds. The
natural form of a Diamond, likewise gives a characteristic to the
purchaser of rough stones; for a fiat, thin, or triangular stone
would lose much in the grinding, and not be so high as to give it
sufficient fire ; and likewise we are not sure of the result of the
cutting, and the hemitrope crystals are very difficult to work. The
best forms of Diamonds for cutting are the octahedron, which is
principally found in the East Indies, and is called Pint by the
diamond grinders, and the rhombic dodecahedron, which is found
principaUy in Brazil ; cheese-stones are the names of amorphous
Diamonds, given to them by the diamond grinders.
According to the quality of the Diamonds, they are divided in
Sumbhulpur into four classes, which correspond with the deities of
the Hindoos — the Bramins, Tschettri, Wassiers (Bysh), and
Tschadrie. The native jewellers are very expert in estimating the
value of these Diamonds.
The value of the polished Diamonds depends on the following
conditions :
Ist^ The Colour. The limpid Diamonds command the highest
price, and twice as much as those that are coloured ; the blackish^
brownish, yellowish, brown, steel-gray, and impure bluish ones,
stand in no value, and are often rejected for working.
2d, The Purity, FauUlessness and Transparency. The
■^
\
TREATISE ON OEMS. 61
Diamonds ought to be, according to the technical terms of the
jewellers, free from ashes, gray spots, rusty or knotty places, veins,
fissures, scratches, feathers, flaws, sand, grains, and faint yellow or
vitreous spots. The Brazilian Diamonds exhibit sometimes, in
their interior, designs resembling mosses, like those of the Mocha
stones and agates ; and we may often observe it in the green Dia-
mond ; if a hmpid Diamond plays somewhat in the brown colour,
it is called shrugging^ and this diminishes its value : paunched,
are those Diamonds which are neither pure nor clear.
The transparency and clearness of the Diamond are divided
into three degrees, viz : —
A, of the first watery as in those Diamonds which are free from
even the slightest faults, and stand highest in price.
B, of the second water, as in those Diamonds which, although
clear and limpid, are marred by some dark spots, clouds, or flaws.
C, of the third water, as in those Diamonds having a gray,
brown, yeUow, green, blue, or blackish colour ; or those that are
limpid, but are injured by several material faults.
In order to determine accurately the nature of Diamonds, it is
well to breathe on them, whereby they lose for a moment their
lustre, and the eye is then better enabled to examine them and
dttdnguish their jfoults. The real Diamond becomes clear much
sooner than the false.
3d, The Cut: The perfect and regular cut of the Diamond
increases its value considerably ; a Brilliant, for instance, of one
carat, is worth twice as much as a rough Diamond of equal weight
It depends upon the proportions of the height to the circumference
of the Diamond, and that the planes and faces stand in a regular
proportion, for should this not be the case, the Diamond would
lose much of its fire. Likewise, the form of the Diamond influ-
ences the price. A Brilliant is dearer than a Rose Diamond, and
this again is dearer than the thick and tablestone. The faces of
the Brilliant also influence the {nice : once cut, is a Brilliant that
possesses no cross facets on the lower part of the stone ; ttaice cut,
there is one row of fricets on the collet-side: thrice cut, the Brilliant
possesses the fecets on the bizel and collet side, according to the
rule of cutting. The more rows of fricets a Brilliant displays the
higher price is put upon it.
4th, Tba Slize and Weight. The price of a Diamond
62 TREATISE ON GEMa
depends considerably upon its size ; those Diamonds which are of
great splendour and size are called Paragons or Nonpareils, the*
Ne Plus Ultra; the less weighty ones are valued according to their
actual weight. The weight employed in Sumbhulpur is the rutta
and masha. Seven rutts is equal to one mash, and one rutt is
equal to two grains. In Brazil the weight is specified by carats
(quilates.) Seventeen and a half quilates are equal to one dram
(octava) ; thirty-two vintenes are equal to seventy grains (graos) y
one carat is equal to four grains.
The price of Diamonds is determined in trade by examining
accurately their character as above stated, and then the price i»
fixed : the weight of the Diamond is at first multiplied by itself,
and the sum obtained multiplied again by the price of one carat
A Brilliant, for instance, would weigh two carats, and on examin-
ing its properties, if good its price would be found to be forty-four
francs. We proceed in the following manner to get at the fidl
value of the Diamond : — 2 x 2 x 44= 176 francs. We do not
always, however, arrive at the correct result. If the Brilliants are
very large, and exceed the weight of eight or ten carats, it ia
difficult to arrive at a standard. I will endeavour to give below a
table of the prices of the Diamond in Holland, France, England,r
and Germany, as far as ascertained, and as near to the actual:
price current as I could be informed.
Rough Diamonds fit for cutting, are worth ten or twelve francs
per carat : any Diamond exceeding the weight of one carat is
estimated by the square of its weight multiplied by eleven or
twelve francs as the avarage price.
For a Brilliant of one carat and first water, the value in
Germany is forty-four fiancs ; of the second water, twenty-eight
firancs.
Rose Diamonds of first water and one carat 20 firancs.
a
II
u
cc
ii
u
a
Brilliants of three grains are in much demand, and are worth
u »
second.
«
13
Tablestone,
-
-
-
14
Brilliants, 30 to 35 pieces
to the c€utit
- 22
" 20
u
((
.<
40
" 10
u
«
«
38
6
u
Cl
«
35
4
«
a
u
36
TREATISE ON GEMS 63
fifty francs per carat. Those of three carats, used for centre-
pieces in necklaces, are sometimes worth four hundred francs.
Rose Diamonds for mounting, and forty to the carat, are worth
twenty francs the carat ; if a little larger, thirty-five francs per
carat.
Diamonds unfit for cutting, and used by glass-cutters or glaziers,
are worth from ten to fifteen francs per carat, and still smaller ones
are worth less ; they are now employed by the lithographers for
their engravings and etchings.
According to Netot, Pujoux, and Lucas, the price of Diamonds
of the first water, were three hundred francs per carat, and second
water, one hundred and fifty.
Diamonds of one grain and less 96 francs per carat.
u a
It <i
u u
u a
a ci
u ti
« ((
u u
u u
u tt
ti «
" of 6 carats — 5000 francs per carat.
The above prices are from Brard's Mineralogie appliquee aux
Arts.
At a most extensive sale of Diamonds which took place in the
^summer of 1 837, at the auction of Rundell and Bridges, London,
there were twenty-four lots put up, which produced the sum
of forty-jive thousand eight hundred and eighteen pminds^
nearly two hundred and twenty-nine thousand dollars ! !
Some of the prices were as follows : — The celebrated Nassauck
Diamond, which weighs three hundred and fifty-seven and a
half grains, and is of the purest water, was purchased for thirty-
six thousand dollars. It is considered to have been sold at a price
considerably under its value. A magnificem pair of brffliant
<ear-rings, weighing two hundred twenty-three and a half grains^
The double cut, first water, 125
u u
6 to a grain, 150
Of 2 grains.
- 170
Of three grains, - - 200
Of one carat.
- 260 to 280
A Diamond of 6 grains, - 600
8 « - 1000
10 " - - 1400
12 " - - 1800
15 « - - 2400
18 « - - 3500
64 TREATISE ON OEMS.
formerly the property of Queen Charlotte, were bought for fifty-five
thousand dollars, a price infinitely below their usually estimated
value. A sapphire, seventy-five and a half carats, set with bril-
liants for a brooch, two thousand four hundred and sixty-five
dollars. Brilliant ear-rings, three thousand seven hundred and fifty
dollars. A brilliant necklace, four thousand three hundred doDars.
Drop emerald ear-rings, two thousand three hundred and twenty-
five dollars. Brilliant ear-rings, four thousand two hundred and
fifty dollars. A Turkish dagger, mounted with brilliants and ruUes,
four thousand dollars. A single brilliant, eight hundred dollars.
A brilliant drop, seventy-nine and a half grains, five thousand
nine hundred dollars. An oblong brilliant, one hundred fifty-one
and a quarter grains, fourteen thousand dollars. A brilliant neck-
lace, eight thousand dollars. Brilliant ear-rings, twelve thousand
five hundred dollars. Brilliant necklace, twelve thousand five
hundred dollars. Brilliant drops, formerly belonging to Maria
. Antoinette, eight thousand eight hundred and seventy-five dollars.
A Rose Diamond, eight thousand five hundred dollars. A brilliani
drop, ten thousand five hundred dollars. A round brilliant, seven-
teen thousand five hundred dollars. A lozenge brilliant, three
thousand five hundred dollars, etc. etc.
On comparison with the prices of those now in market, it is
certain they have much declined, which is partially to be attributed
to the immense stock which has been brought firom their native
locality. According to Spix and Martias, there have been produced
in Brazil, firom 1772 to 1818, 1,298,037 carats of Diamonds, that
is in the time of the Royal Administration ; but that during the
Lease, only 1,700,000 carats were produced, which together make
2^998.037 carats, or 1301 1-4 pounds; thus averaging fix)m four-
teen to fifteen pounds per year; those brought into msurket by
contraband being excepted. The value of the above Diamonds^
(8,000 reis per carat,) produced in Brazil, anMnints to 23,984,276,
000 reis, or about 40,000,000 francs ; this sum bears no comparison
to the expenses of procuring them, since the government lately
paid forty francs, fifty cent per carat, whereas they only yielded
from eighteen to nineteen fraivcs. On this account, the adminich
tiation at Rio de Janerio has been induced to lease the mines to
private individuals. Owing to this decrease in the production,
the number of labourers is reduced. The jddwst piod^eUcflt wai
t
TREATISii ON OEBli 65
iH^ 1784, when fifty-si^ thousand one hundred and forty-five carats
iMN^ washed out, and the poorest in 1818, when they procured
hxxi nine thousand three hundred and ninety-six carats. In
Brazil, large Diamonds are much rarer than in the East Indies,
where they are in general of much better quality than in Brazil.
iQ'tfae latter country, from 1772 to 1811, they found but thirty-sir
Diamonds, weighing upwards of seventeen carats, and from 1812
to 1818, but eighty-three Diamonds weighing over eight carats.
In the East Indies, according to Breton, from the year 1804 to
181 8, there were found in Mahanues, twenty large Diamonds, the
aggregate weight of which amounted to four hundred and thirty-
six carats and one ^in. The largest was found in 1809, and
weighed six hundred and seventy-two grains, but was of the
third water; another of three hundred and eight grains, and
another of two hundred and eighty-eight grains.
As it has already been stated that the artist and amateur have
to be on their guard against imposition in the purchase of
Diamonds, it maybe well to state that there is the one-half
brilliant, having the form of a brilliant above (the upper pyramid)
but no lower pyramid ; or another stone is pasted on by means of
mastic. The character of the stone is readily detected when
taken out'Of the mounting.
Sapphires, Hyacinths and Topazes are sometimes slightly
calcined and sold for Diamonds. The first two are heavier than
the Diamond ; they are, however, harder, and possess more fire.
The Topaz is distinguished by its property of becoming electric
when heated.
Rockcrystal is much lighter, but brilliant and hard ; and the
same character is applicable to the strass.
The following list shows the size and in^eight of the most
interesting Diamonds in the poersesdion of difiereht sovereigns.
I. The largest Diamond is in the possession of the Grand
Mogul, and according, to Tttvernier, resembles in form and size
half a hen's ej^. Its weight is two hundred and ninety-seven
and three-sixteenths carats. It was found in 1552, in the mine
of Colore, a short distance t6. the east of G61cond&,'and is valued
at four riiSlions of fi*anc8. It is cut as a Rose Diamond, and is
perfectly limpid, with thb exception of a small* flaw at the^end^of'
thto' girdfci
66 TREATISE ON GEMS.
n. The Diamond in the possession of the Rajah of Mattan, in
' Borneo, weighs three hundred and sixty-seven carats : it was found
on that island. It is of an egg forpci, has a cavity towards the
thinner ei^d, and is of the first water.
III. The Diamond belonging formerly to Nadir Shalx, Sultan of
Persia, and now in the possession of the Russian crown,'; weighs
one hundred ninety-four and three-fourths carats. It is of the first
water, without flaws or faults of any kind. Its form is that of a
flattened oval, about the size of a pigeon's egg, cut in a pyramidal
form ; it is one inch three lines in diameter, and ten Unes high.
It was purchased by the Empress Catharine for about ninety
thousand pounds, cash, and an annuity of four thousand pounds,
but is considered of more value.
lY. The Diamond in the treasury of Rio Janeiro, was found in
1771, at Rio Abaite, by three criminals, who delivered it to the
government, for which they were pardoned. It weighs one hun-
dred and thirty-eight and a half carats.
V. The Austrian crown possesses one which weighs one hundred
and thiity-nine and a half carats, and is valued at one hundred and
nine thousand two hundred and fifty punds. It is beautiful and
well formed, but its colours turn towards the yellow.
There is another belonging to the crown, which was formerly in
the possession of Charles the Bold, of Burgundy, who lost his all
in the battle of Granson, and likewise this Diamond, which was at
that time the largest in Europe. A Swiss soldier, who was the
robber thereof, sold it for a crown dollar to a priest ; and after pass-
ing through several hands, it was purchased by Pope Julian II.
for twenty thousand ducats.
VI. The Regent or Pitt Diamond, now belonging to the crown
of France, is said to have been in Malacca,, and was purchased by
Mr. Pitt, then governor of Bencoolen, in Suinatra, and sold by
him to the Regent duke of Orleans, by whom it was placed among
the crown jewels of France. It weighs one hundred and thirty-six
and three-quarters carats; is cut in the form of a brilliant, and is
of the first water, being absolutely faultless. When rough, it
weighed four hundred and ten carats, required two years labour in
cutting, and is worth, according to the value put by a commission
of jewellers, in 1791, twelve millions of livres.
YII. Another Diamond, the Sancy, one of the largest and most
TREATISE ON GEMa 67
beautifully coloured, likewise belongs to the crown jewels of France.
It is of a pear form, cut as a double Rose Diamond, and weighs
one hundred and six carats. It was bought for six hundred thou-
sand livres.
VIII. Another Diamond, belonging to the crown jewels of
France, is of a rich sky-blue. It weighs sixty-seven and an eighth
carats, and is valued at three millions of livres.
IX. A rough one, found in the river Abatio in Brazil, is in the
possession of the Prince Regent of Portugal, which weighs an
ounce troy.
X. The two large Diamonds belonging to the Shah of Persia,
have already been mentioned in the first part, with accompan]/ing
figures.
XI. The Turkish crown has two very large Diamonds ; one of
eighty-four carats, and the other of one hundred and forty-seven
carats. The latter is valued at eighty thousand ducats.
XII. One found in Brazil, in 1780, weighs seventy-two carats
and three-fourths grains. Another, found in 1803, weighs seventy
carats. They are both at Rio Janeiro.
XIII. The largest of all known Diamonds is said to be in the
possession of the king of Portugal. It was found in Brazil, in the
diamond district, and is as yet in its rough state. It is of the size of
a chicken's egg, weighing one thousand six hundred and eighty
carats, (above eleven ounces) ; and is estimated in value at fifty-
seven million pounds sterling. It is now the general opinion of
jewellers and mineralogists, that this is a white Topaz.*
Description of the Crown Jewels of Queen Victoria /., worn
at her coronation, 28th June, 1838 : —
The crown in which her majesty appeared at the ceremony of
the coronation, was made by Messrs. Rundell and Bridges. It is
exceedingly costly and elegant; the design is much more tasty than
that of the crown of George IV. and Vfilliam IV. which has been
broken up. The old crown, made for the former of these monarchs,
• I have been informed by Mr. Featherstonehaugh, the U. S. Geologist, that he
has discovered perfect crystalized Diamonds (a green and a white) south of the
Potomac ; and Mr. Thomas G. Glemson, of Philadelphia, kindly exhibited to me
his Diamond, found in North Carolina, weighing one and a half carats, and having
a distinct octahedral form,
68 TREATISE ON GEMS.
weighed upward of seven pounds, and was much too large for the
head of her present majesty. The new crown weighs little more
than three pounds. It is composed of hoops of silver, enclosing a
cap of deep purple, or rather blue, velvet ; the hoops are completely
covered with precious stones, surmounted with a ball, covered with
small diamonds, and having a Maltese cross of brilliants on the
top of it.
The cross haa in its centre a splendid Sapphire ; the rim of the
crown is clustered with brilliants, and ornamented with fleurs-de-
lis and Maltese crosses equally rich. In the front of the Maltese
cross which is in front of the crown, is the enormous heart shaped
ruby, once worn by the chivalrous Edward the Black Prince, but
now destined to adorn the head of a virgin dueen. Beneath this,
in the circular rim, is an immense oblong sapphire. There are
many other precious gems, emeralds, rubies, and sapphires, and
several small clusters of drop pearls. The lower part of the crown
is surrounded with ermine. It is upon the whole a most dazzling
and splendid crown, and does infinite credit to those by whom it
has been designed and put together. Her majesty has expressed
herself highly pleased with it.
The following is an estimate of the value of the jewels :
20 diamonds round the circle, 1,600/. each, - 30,000
3 large centre diamonds, 2,000/. each, - - 4,000
64 smaller diamonds placed at the angles of the former, 100
4 crosses, each composed of 26 diamonds, - - 12,000
4 large diamonds on the tops of the crosses, - 40,000
18 diamonds contained in the fleur-de-lis, - - 10,000
18 smaller diamonds contained in the same, - 2,000
Pearls, diamonds, &c., on the arches and crosses^ - 10,000
141 diamonds on the mound, .... 500
26 diamonds on the upper cross, ... - 3,000
2 circles of pearls about the rim, ... 800
*111,000
TREATISE ON GEMS. - 69
CORUNDUM.
The above name yyos applied to a difierent species from that of
Sapphire ; but these terms are now generally acknowledged to be
synonymous ; not so,' however, the emery, which does not belong
to this species.
Both occur in rhomboids, often too in crystals of secondary form.
They scratch all other gems except the Diamond. Their streak
and powder are white ; and the speciiSc gravity is 3.9-4. They
acquire electricity by rubbing, which is retained for several hours.
They are not fusible before the blowpipe. With diflSculty, by
means of borax, they form a clear Umpid glass. Acids have no
effect on them. Their chemical constituents are alumine, silica,
and oxide of iron.
II. SAPPHIRE.
This name b derived probably from the Hebrew, as it is ofUsa
mentioned in the Bible. It is not certain whether the ancients were
acquainted with merely the blue variety of this gem, and were
ignorant of other blue stones, such as Lasulite, Fluorspar, &c. It
was not used by them as a gem, probably on account of the diflS-
culty of working it ; but as a medicine, many pecuUar virtues were
ascribed to it. This species has hitherto been usually divided ac-
cording to its different colours. The name of Ruby has reference
to a red colour, and was applied by the ancients to the Carbuncle.
Sapphire occui*s in crystals, in rounded grains and pebbles. It
is generally transparent ; but sometimes only translucent, or dis-
plays a shine of light of six rays, resembUng the form of a star.
It possesses double refraction in a slight degree, and a vivid vitreous
lustre, which sometimes turns to that of mother of pearl. Its
fracture is from conchoidal to uneven. Its principal colours are
blue and red, with their various shadings ; sometimes white, gray^
yellow, green, brownish-green, and black.
If the red Sapphire (Ruby) is exposed to a great heat, it becomes
green, but when cold, returns to its original colour : the green Sap-
phire undergoes no changes.
The various names given to Sapphire, according to its colour,
are: —
1st. Ruby, (oriental Ruby) of a dark crimson red, cochineal or
cfgrouoc^ and tose-red mostly inclining ta videtrUue.
70 TREATISE ON GEMS.
a. Oriental Hyacinth, aurora-red.
2d. Oriental Amethyst, paleish violet-blue. Playing sometimes
in rose and purple-red, like the common Amethyst, except in its
superior lustre.
3d. White Sapphire, limpid and perfectly transparent; vivid
lustre, resembling the Diamond.
4th. Sapphire, Oriental Sapphire, from the darkest to the lightest
blue v^ith different shadings, whence it is denominated by difierent
terms, such as Male Sapphire^ of a perfectly clear Berlin or smalts
blue ; Female Sapphire^ full blue, with a tinge of white ; some-
times sky-blue, with streaks or specks. Water Sapphire^ very
pale-blue, and sometimes discoloured. Cat-iSapphire, blackish or
greenish blue, often not transparent.
5th. Oriental Topaz ; lightly yellow, lemon or brownish straw-
yellow ; sometimes playing into green ; it is distinguished from the
common or true Topaz by colour and lustre ; but it occurs likewise
much larger, and is seldom less free from faults than any other
species of Sapphire.
6th. Oriental Aquamarine; greenish blue, pure and transparent;
possessing a higher lustre and greater hardness than the common
Aquamarine.
7th. Oriental Chrysolite, or Peridote ; yellowish-green, resemb-
ling in colour the Chrysoberyl, but may be distinguished from it by
its higher lustre.
8th. Oriental Emerald ; green, more or less dark, inclining to
yellow ; it does not equal in colour the real emerald, but possesses
a higher lustre, and is at the same time very rare.
The Sapphires which sometimes display a peculiar play of light,
are divided into : —
1st. Star-Sapphire, (Asteria, Opalescent, or Chatoyant Sapphire.)
Some translucent Sapphires display, if held before the sun, or a
burning taper, a white light running in six rays, resembling three
white planes, or stripes crossing themselves at one point. This
property is thus visible when the Sapphire is cut convex (or cabou-
chon), and when the principal axis of the crystal stands perpendi-
cidar to the base of the convex cut stone ; these Star-Sapphires are
either called Ruby-Asteria, Sapphire-Asteria, or Topaz-Asteria,
according to the colour they bear.
2d. Girasol-Sapphire, Oriental-Oirasol, Sunstone, Sapphire, or
TREATISE ON GEMS. 71
Ruby cat's-eye, have a yellowish, reddish, or bluish shine, or reflec-
tion of light, generally of a lighter colour [than the stone itself,
displayed when moved or turned on the convex surface. The
difiereut varieties of Sapphires are found in the sand of rivers, or in
boulders, with Garnets, Zircons, and other gems, in Ceylon, China,
Siam, Brazil, Bohemia, France, Saxony and the United States.
It has been observed that the blue Sapphires are frequent in Ceylon
but not the Rubies : and tliat in Pegu it is the reverse. We also
find the Sapphire in basalt. The most celebrated mines of Sapphire
are at Mo-gaot and Kyat-Pyan, five days journey from Ava. The
Boa, or emperor of the Birmans, retains all the larger Sapphires.
For cutting a Sapphire an iron mill is used, and for polishing,
a copper mill, or one made of an alloy of lead and tin, to which a
horizontal motion is given by a very simple machinery ; its sur&ce
is charged with diamond powder and oil, or with fine emery and
water. A thick peg or guage of wood, pierced with small holes in
all directions, is set upright on the lapidary's bench, close to the
mill. The stone, being placed on the surface of the mill, and the
opposite end of the stick to which it is cemented being inserted in
one of the holes of the guage, the mill is put in motion by turning
a winch, and the stone kept steady on it.
When the stone has all the facets, the cutting mill is taken out
and replaced by one of brass, on which the polishing is performed
by means of fine emery and rottenstone, in the same manner as
before. A good judgment is required in determining the form and
proportions best adapted to set ofi* any particular stone to the best
advantage. If the colour is full and rich, its transparency perfect,
and its refractive power considerable, the best form to give it is
the brilliant. If, on the contrary, the colour is dilute, the most
advantageous method of cutting it is, to cut the table side (pavilion)
brilliant fashion, and the collet side (culasse) in steps ; by this
means the table itself will be left dark, while all the light reflected
firom the steps on the under side of the stone will be thrown up
into the facets, by which the table is surrounded. The French
lapidaries cut the most perfect Sapphires in a square or octagon
form, with a single delicate step between the table and the girdle,
and three or four steps between the girdle and the collet.
If the Sapphires possess a varying chatoyant lustre, or are of a
73 TREATISE ON GEMS.
small size, their form is always hemispherical or elliptical, without
any flat facets ; the fiater the ellipse, the more the- varying lustre
is diffused over the surface of the stone ; whereas with a high
ellipse it is condensed on a single spot.
In setting Sapphires, we always use foil answering to their
colour. The Ruby is set with a reddish gold foil, or a foil of copper
or red glass : the blue Sapphire with a silver foil, or blue-coloured
foil, or with feathers of blue ducks, pigeons, or peacocks, and the
water Sapphire in a black back ; but all perfectly pure Sapphires
are set a jour*
Many Sapphires may be deprived of their specks by a careful
calcination in a curcible filled with ashes or clay, and they assume
then a more agreeable and purer colour and greater transparency.
Sapphires are very favourite gems, and are extensively used by
jewellers for setting in pins, rings, &c. In China, the ladies'
slippers are mounted with Rubies.
The blue Sapphires have of late been employed as lenses for
microscopes with great success. According to Brewster, it isj for
its refracting power, second only to^the Diamond; and superior to
all other gems. A new use has lately been made of the Sapphire
for drawing wires ; it being cut in the form of a wedge, through
which, by means of a Diamond-point, a circular hole is drilled and
then fastened on a brass-plate ; the wire is drawn through the
smaller aperture of the Sapphire towards the wider, by which
process it is reduced to a thinness never otherwise attained.
The price of Sapphires is very relative, but their proportional
value is next to that of the Diamond. The Oriental Ruby stands
highest in value, and when perfect, and exceeding three carats, is
generally as dear as a Diamond of equal weight and quality.
After the Ruby, blue Sapphire stands next in value ; and as this
is not so rare, and occurs in large specimens, it is not so high in
price. Some put the price of the blue Sapphire equal to that of
the coloured Diamonds. Others put the price at half that of a
Brilliant under similar circumstances. Sometimes the value is
fixed by multiplying half the price of a Sapphire weighing a carat,
with the square of its weight. It is therefore very difficult to come
at an exact price current ; and the following average prices come
nearest to their commercial value :
TREATISE ON OEBIS.
73
ROBT,
Of 1 grain weight -
2 francs.
2
3
1
2
3
4
5
U
U
carat
u
tc
il
u
« -
((
It
It
ti
a
■ 6
12
20
60
150
250
350
a
((
cc
a
u
a
u
BLUE SAPPHIRE.
1 carat
2
«
10 francs.
20
3
4
5
6
8
10
((
(C
ii
a
u
a
a
a
u
(C
« 30
« . - . . 45
« 60
« ... - 80
« 100
« .... 200
Smaller stones 8 to I carat are worth - 8
12tol « « - - 6
16to24tol « - - - 4
In order to show the various prices of the Rubies, we cite the
sale at auction of the Marquis de Dree's collection, at Paris : —
For a cherry-red Ruby of
For a darker Ruby of
For a bluish-red Ruby -
For a lighter Ruby - -
For a blue Sapphire - -
For an Indigo-blue do. -
For a light blue do. - -
For a white do. - - - -
For an Oriental Amethyst
For a fine yellow Topaz - 6 1-2
For a lighter Topaz - - 6 1-4
There are numerous faults and defects to which Sapphires are
subject, and which always influence their price, such as clouds,
milky or semi-transparent specks, like Chalcedony, white stripes,
fissures or knots, &c. The Sapphire, particularly the red and blue
varieties, being great &vourites in commerce, are often imitated,
- 2 caratjs, -
1000 francs.
11-2
«
400
tc
. 21-2
«
1400
u
3
«
1200
u
6 -
«
1760
u
- 63-4
a .
1500
a
4 -
u
123
u
4 1-2
u .
- 400
iC
11-2
«
400
(C
6 1-2
« -
- 620
a
6 1-4
« - -
71
iC
74 TREATISE ON GEBiS.
not only by means of other coloured gems resembling them, but
also by substituting pastes. Instead of Ruby, we sometimes get the
Spinelle, Garnet, Hyacinth, red Quartz, calcined Amethyst, red-
burnt Brazilian Topaz, red Tourmaline ; and instead of the blue
Sapphire, we get the Disthene, Cyanite, and the Cordierite, — the
hardness is the best test.
NOTICE OF SOME LARGE SAPPHIRES.
Tavernier describes two large Rubies said to have belonged to
the king of Yisapur, one of which weighed fifty and three-<}uarter
carats, and the other seventeen and a half carats. The first
was valued at sixty thousand francs, the other at seventy-four
thousand five hundred and thirty fi^ncs.
The king of Pegu and the monarchs of Siam monopolize the
fine Rubies, as the sovereigns of the peninsula of India have
done the Diamonds.
The finest Ruby in the world, is in the possession of the first ;
its purity has passed into a proverb, and its worth, when compared
with gold, is inestimable.
The Subah of the Divan is also in the possession of a prodi-
giously fine one, a full inch in diameter.
The Empress Catharine, of Russia, possessed one Ruby of the
size of a pigeon's egg.
Blue Sapphires are described by the English embassy to Ava,
of the weight of nine hundred and fifty-one carats. Mr. Mawe
saw a blue Sapphire of three hundred and ten carats. In the
. crown jewels of France, there is one rhomboidal crystal of one
himdred and sixty-six carats.*
m. (X)MMON CORUNDUM, DIAMOND SPAR.
This mineral was formerly brought from China only, when not
so well known as at present, and bore the name of Common
Corundum, but it is now considered as belonging to the general
fiBimily of Corundum. It occurs in crystals which are generally
coated with some crust ; it has a conchoidal firacture, is translucent,
* Amost valuable collection of rough and polished gems, and paiticularly of lh«
Sapphire family, I have seen in the possession of Robert Qilmore, Esq., of Balti-
more. Mr. Featherstonhaugh exhibited to me a rough Ruby with a native grain
of Platina from North Carolina. In Mr. Clemson's collection of Cameos is an
antiqiie head, cut in a large Sapphire of about twelve cai«ts«
TREATISE ON OEMS. 75
and has a lustre between unctuous and mother of pearl, either
gray, red, blue, green, brown, or whitish in different shadings. It
is mostly inclosed in granite, mica slate, dolomite, or magnetic iron,
and is found in Piedmont, Cananore, Campo Longo, the East
Indies, and Sweden.
All the Corundums, possessing fine and pure colours, are used
and cut as jewels, and the impure pieces are pulverized and used
for cutting and polishing harder stones, or glass and meta](|,
particularly so in the East Indies and China, and it b called, in
Madras, the grinding-spar.
IV. CHRYSOBERYL.
The name of this gem is derived from the Greek, and is expres^
eive of its colour ; it is also called Gymophane. It was formerly
classed with the Beryl family, but was separated from that by
Werner.
It occurs, crystallized, in a prismatic form, also in boulders and
grains ; is transparent to translucent, and possesses double refrac-
tion in a high degree ; its lustre is between unctuous and vitreous ;
firacture conchoidal ; its colour asparagus, and olive-green with a
tinge of brown, yellow, gray or white. Some specimens display,
sometimes, a milky or bluish-white lustre. Chrysoberyl scratches
Topaz, and Rock-crystal very distinctly, but is attacked by
Sapphire ; the streak-powder is white, specific gravity, 3.69 — 3.75*
It becomes electric by rubbing, and retains this property for several
hours : it is infusible by itself before the blow-pipe, but is slowly
fiisible into a glass bead with borax. Its component parts are, —
alumina, silica, and glucia, with some oxide of iron and titanium.
In commerce Chrysoberyl is called Oriental Chrysolite, and that
displaying the lustre is called Opalescent Chrysolite.
Chrysoberyl is mostly found in loose crystals or in boulders in the
sand of rivers associated with other gems, such as Spinelle, Sap-
phire, Topaz, Beryl, &c. In Brazil, particularly in the diampnd
district, and more frequently in Termo Minas Novas, Pegu, Ceylon,
and Siberia : likewise in Connecticut, (at Haddam,) and in New
York, (at Saratoga,) embedded in coarse granular granite, and
accompanied by Garnet and Beryl.
The Chrysoberyl is cut on a brass wheel with emery, and
polished on a pewter wheel with rotten stone ; it is very often cut
76 TREATISE ON GEMS.
en cabouchon, and if perfectly pure and transparent in other forms,
is set with gold foil, and is used for rings and pins.
The Chrysoberyl is in no great estimation on account of its
indiffeient fire and colour, but taking a high polish, and occurring
transparent and pure in colour, those of varying lustre, are of some
value ; it is particularly worn in Brazil. At Paris a Chrysoberyl
t)f fine green colour, oval cut, seven lines in length, and five and
three-quarters in breadth, was sold for six hundred fi*ancs, and a
very fine Opalescent Chrysoberyl nearly five lines long and {our
broad, cost six hundred and three fiancs.
For Chrysoberyl, has been substituted Apatite, Fluorspar, and
pastes ; but it is harder than all ; Chrysolite bears a great resem-
blance to Chrysoberyl in its external appearance, but is much
lighter and softer. A green Chrysoberyl was found in Termo of
Minas Novas, which weighed sixteen pounds, the largest known.
It is in the possession of the crown at Rio de Janeiro.
V. SPINELLE.
This gem was called by the ancients. Carbuncle. It only occurs
crystalized, and mostly in the form of an octahedron, and its mod>-
fications. The crystals are smooth, solitary, or grown together as
hemitropes, loose, often rounded like grains ; its fracture is conchoi-
dal ; it is transparent and translucent ; it possesses simple refirac-
tion of light ; is of a high vitreous lustre ; and its colour is red,
turning into the greatest variety of shadings of blue, brown, and
yellow. Sometimes we find, likewise, blue, black, and green
Spinelle, which, however, have no commercial value, on account
of their impure colour and want of transparency.
Spinelle scratches duartz, and is attacked by Sapphire ; becomes
electric by rubbing ; its specific gravity, 3.48 to 3.64 ; is inftisible
before the blowpipe. According to Berzelius, the Spinelle of Ceylon
when heated, grows first brown, then black, and then opaque,
which on cooling, passes into green and limpid, and ultimately into
its original red. Acids do not affect it ; its component parts are
magnesia and alumina. The Spinelle is classed by the jewellers
and lapidaries according to its various colours.
1. Ruby Spinelle, or Spinelle Ruby ; of a light or dark red, and
no milky lustre ; shows, if held near the eye, A tinge of rose-red
colour. ?--
TREATISE ON GEMS. 77
2. Ruby Balais, or Balais Ruby ; pale-red or rose-red, sometimes
with a tinge of brownish or violet.
3. Almandine Ruby ; of a cochineal-red colour, bordering on
blue, violet-blue, and reddish-brown ; it is distinguished from the
Garnet, likewise called the Almandine, by its lighter colour,
stronger lustre, and greater hardness.
5. Goutte de Sang, is a fine cochineal or blood-red Spinelle.
Spinelle is found in clay, and in the sand of rivers, with Sapphire,
Garnet, Tourmaline, and other gems. In Ceylon, Pegu, and Can-
anore, it is cut on an iron or brass wheel, with emery or pulverized
diamond, and is polished either on the same or on a copper wheel,
with oil of vitriol.
Spinelle is cut in the same form as the Diamond, and is set with
a foil of co[q)er or gold. Its colour is often made more intense, and
its &ults, such as flaws and specks, removed, by calcining it care-
fuHy.
Lustre, colour, and hardness, have made the Spinelle a very
fevourite gem, which is used in a great variety of ways, as in rings,
pins, necklaces, &c.
As to the price of Spinelles, it is difficult to~ determine with
accuracy, as so much depends on their properties. If in perfection,
it exceeds four carats, it is usually worth half the price of an equally
large Diamond. The Spinelle Ruby and Balais Ruby are the most
esteemed Spinelles, and if of twenty-four to thirty carats, are worth
from two hundred to four hundred francs ; and such gen)s are often
sold for the true Rubies, (Sapphire.)
Zircon is of greater specific gravity and less hardness than the
Spinelle, and shows strong and double refraction of light. Calcined
Topaz is distinguished by its electric properties. Burnt Amethysts
are lighter, and are scratched by Spinelle. Pastes are hkewise
substituted for the Spinelle, such as glass coloured with gold-purple;
but as the Spinelles are always harder and heavier, the adultera-
tions may soon be detected.
VI. TOPAZ. ,
It is not determined whether the ancients meant by« Topaz the
same gem as we describe, since the Greeks understood the Topaz
to be of a transparent gold-yellow, and the Romans of a transparent
green-yellow. The name, which, according to Pliny, is derived
78 TREATISE ON GEMS.
from Topazos, an island in the Red Sea, has no reference to its
colour. Topaz was, in former times, thought to possess great
medicinal virtues ; for example, as a remedy for mania, and as a
strengthening medicine. The Topaz occurs crystallized in a
rhombic prism, but mostly in very complicated forms, particul^ly
the Brazilian, Siberian, and Saxonian, and is also found in boulders.
Its fracture is conchoidal ; it is transparent and translucent ; pos-
sesses some double refracting powers ; a very vivid vitreous lustre ;
clear, straw, sulphur, wine and gold-yellow colours, sometimes with
a tinge of violet-blue, greenish and white. Topaz scratches dis-
tinctly duartz, but is attacked by Sapphire. Its streak-powder is
white ; specific gravity is — 3.49 to 3.66 ; it is phosphorescent when
heated, with a bluish or yellowish lustre, in small fragments. It
becomes electric either by rubbing, heating, or by pressure, and
retains the property for more than twenty-four hours. Before the
blowpipe at a strong heat, it is covered with many small bubbles,
and partly loses its colour. It is dissolved, fusing slowly with borax,
into a white bead : acids have no effect upon it Its component
parts are alumina, silica, and fluoric acid.
In commerce. Topaz is distinguished by the following names:—
1. Water Drops, pebbles (gouttes d'eau) clear, limpid.
2. Siberian Topaz, white, with a bluish tinge.
3. Brazilian Topaz, gold-yellow, with a touch of reddish.
4. Saxon Topaz, pale wine-yellow.
5. India Topaz, saffron-yellow.
6. Brazilian Ruby, light rose-red.
7. Brazilian Sapphire, light blue.
8. Aquamarine, sea and mountain green.
Topaz belongs to primitive rocks, and is found in chlorite slatCi
gneiss on gangues, argillaceous shiste, &c. : in Siberia, (Mursinsk
and Miask,) Brazil, Scotland, Saxony, Bohemia, and in the United
States, (at Huntington, Conn.)
In Brazil, it is found in a decomposing chlorite slate, (and is
there called malacheta,) within brown hematite cavities or quartz
g^ingues, and are of one inch to one and a half feet thick, and are
overlaid by indurated talc, and white and brown kaolin, that is
sometimes intermixed with quartz crystals and micaceous iron,
which are the surest indications of Topaz. Such Topaz localities
are at Tilla Rica and Capao and Lana. Little attention is paid
TREATISE ON GEMS 79
during the dry season to the dicing of Topaz ; but with the
beginning of the rainy season, the searches for Topaz are under-
taken, and the operation for washing and procuring them is per-
formed tike that of the diamond, mentioned under its proper head.
In places where the Topaz is found in company with tin ore, it
is picked out, but where it forms a part of the rock, it is wrought
by mining operations, as in Saxony.
Topaz is cut on a leaden wheel, either with emery or pulverized
Topaz, and is potished on a copper wheel with rotten-stone. Care
has to be taken in sUtting the foUage. The forms which it is to
receive depend upon its quaUties and purposes. The white Topaz
is cut in brilliant form, with a small table ; the bluish Topaz, how-
ever, is cut with a mixed form, but it is to be observed that the
table-side requires to be higher than usual, the table smaller, and
the colletrfiide, with its steps, must be attentively wrought in pro-
portional distance. The yellow Topaz is mostly cut as briUiant
or table stone, and in setting, its back is suppUed with a gold foil,
and the pale with a red-coloured foil. Many species of Topaz are
set a jour. Topaz assumes by calcining a different colour, and
also by colouring fluids, as already stated in the introduction.
The Topaz is in general use by jewellers for setting in rings,
pins, ear-rings, seals or necklaces. Its fragments are pulverized and
used for grinding the softer precious stones; this is effected by
calcining them first, then throwing them into water, and afterwards
pulverizing them. Tq[)az is generally of less value now than
formerly, owing to the yearly supplies obtained from Brazil, which
is about forty pounds. The mine at Gapao has yielded about
twelve thousand dollars worth, and the supply has been accumu-
mulating at Rio de Janeiro and Bahia to such a degree, that it is
disposed of at a less price there than at the mines.
Those most esteemed are the rose-red and the white, or water
drops, pingos iPagoa. A Topaz of the size of a bean is sold at
Chapada in the Termo of Minos Novas, at one dollar ; one of one
oarat, is di^x)8ed of at an average rate, for eight dollars ; a yellow
one, for three dollars ; and a yellow burnt one, for five dollars. In
Brazil, veiy large, fine and lustry ones bring thirty dollars.
The Saxoniian Topazes are less valued, yet good yellow or
erimson-cofeiHred ones, nine lines long and seven broad, bring four
hundred aad twenty firancs.
80 TREATISE ON GEMflt
Aquamarine and Chrysolite are sometimes substituted for Topaz;
but it may easily be distinguished from them, not only by ita
hardness, fracture, and specific gravity, but more especially by its
property of becoming electric by rubbing. This will prevent the
substitution of either of the above, or those most resembling them ;
such as the yellow quartz, chalcedony, or other yellow-coloured
stones.
According to the account of Tavernier, the Grand Mogul pos-
sesses an octangular polished Topaz of one hundred and fifty-
seven and three-quarters carats weight, which has been purchased
for sixty thousand dollars.
M. d' Eshwege notices a Topaz crystal ten inches in length and
four inches in diameter. The United States (Coimecticut) yield
Topazes of an opaque colour, pale, dark orange, and yellow, twelve
inches in length. One of the finest Brazilian Topazes I have
seen, is in the rare collection of Robert Gilmore, Esq., of three
inches length, and perfectly terminated.
- EMERALD.
The proper Emerald and the Beryl belong to this mineral species,
and are distinguished by their colour and crystalline form. The
Emerald occurs in six-sided prisms with their modifications ; it
scratches quartz, and is scratched by Topaz. The streak-powder
is white ; its specific gravity is 2.73 to 2.76 ; it becomes electric by
rubbing ; it is rounding before the blowpipe, and forms an opaque
black, but becomes a green or limpid glass, having the hardness of
borax. Its constituents are glucia, alumina, and sihca.
VII. (A.) THE PROPER EMERALD.
The Emerald appears to have been known in the most remote
ages, and was the third stone, according to Calmet's arrangement,
on the high-priest's breast-plate of judgment, with the name of
Zebulon inscribed on it. In the time of Pliny, this stone was hdd
in such high estimation, that it was seldom if ever engraved upon.
The modems, however, did engrave on the same, as we find in the
royal collection at Paris a head of Henry IT., and one of Louis
XIY. It has been excavated from the ruins of Rome and from
Herculaneum and Pompeii. But the ancients often included under
this name other gems of the same colour ; such as the green fluor.
* tUEATISE ON GEMS. 81
Aquamarine, Jasper, Malachite, <fcc. They appear to have obtained
the Emerald from Egypt. CaiUoud has in modern times succeeded
in finding the old Emerald mines in the Theban deserts, on the
Arabian Gulf, which have been noticed by the ancient authors and
by the traditions of the Arabs, as coming from the mountains of the
Zaharah, when sent on an exploring expedition by the Pasha of
Egypt. He mentions having found subterranean mines, capable
of allowing four hundred men to work ; and he likewise found
tools, ropes, lamps, and other utensils. He judged from the ruins
of the architecture of the temples of a city which he discovered,
that they were of Egyptian or Grecian form, and about one thou-
sand years old.
Among the church treasures of the ninth and tenth centuries,
we find the Emerald, which came into particular notice after the
conquest of Peru, where an Emerald of the size of an ostrich egg
is said to have been idolatrized by the savage inhabitants. The
Emerald was formerly used as medicine, and was worn as a pre-
ventive against epilepsy.
The Emerald occurs in somewhat depressed six-sided prisms ;
the lateral faces of which are smooth ; the fracture is conchoidal
to uneven ; it is transparent to translucent ; displays double refrac-
tion in a slight degree ; has a vitreous lustre ; is green and emerald-
green with its different shades.
It is scratched by an English file, and scratches strongly white
glass, and slightly quartz. Its specific gravity is 2.73 to 2.77. Its
colour is owing to the oxide of chrome. An Emerald when cal-
cined, and thrown info water, crumbles into pieces of different
colours. The purest Emeralds are called the Peruvian.
The Emerald is found in micaceous shiste at Salzburg, in the
Zaharah mountains, on gangues in Peru, in the argillaceous and
in hornblende slate. Formerly, the finest Emeralds came from
Warta, in Peru ; but the mine is either exhausted, or the Indians
have filled up the mines before they left them at the conquest.
The best are now found in the valley of Tunca, in Ssmta Fee,
where they occur in granite. The Emerald has lately been disco-
vered in Siberia, in the micaceous shiste, and is equal to the Peru-
vian in every respect.
The Bmemld is sawed into pieces with emery, cut on the copper
82 TREATISE ON QEMS.
wheel,, and polished on a finer wheel with rotten-^tone, pumice-
stone, tin ashes and water. The step-cut, and the mixed step-cut,
or the table-cut, are mostly used, yet it is sometimes cut as a brilliant
or rose-cut. They are set with a green foil or green satin on their
back ; or sometimes in a back coloured with mastic, and veryUack;
but if perfectly pure, and of fine colour, they are set a jour. On
exposure to air, Emeralds grow by degrees paler.
The Emerald is, on account of its agreeable green colour, a very
favourite ornament ; and b used for the most expensive kind of
jewellery. Its value depends altogether upon its pure and fine
colour, vivid lustre, and the size of the specimen. The price of
Emeralds was much higher before than it has been since the
discovery of Mexico ; the product of the mines of Peru reduced
their price considerably ; now they are getting again dearer, and
command always a good price. A small box of fair Emeralds from
Peru, which I saw a few years ago, at the ofiice of the American
and Foreign Agency, in this city, which weighed from three to four
pounds, was sold afterwards at Paris for nine thousand firancs.' A
good Emerald, of fine colour, is worth twelve dollars per carat : and
the price increases according to its interior qualities. The price of
the best Emeralds of
4 grains
is
18 dollars
8 «
C£
30 «
16 "
tt
200 «
24 «
«
300 «
48 «
((
1000 «
An Emerald of 24 grains, and good colour, was sold at the
auction of the Marquis de Dree, for two thousand four hundred
fi-ancs. Emeralds of indifferent pale colour, are sold for two dollars
per carat. The faults which the Emeralds are subject to are,
inequality of colour and transparency, dark or white spots, fissures
and feathers.
For Emerald, there is sometimes substituted the green Tourma-
line and Apatite ; the former is easily detected by its property of
becoming electric by heating ; but in general all these stones do
not possess the lustre and hardness of the Emerald. The pastes
in imitation of the Emerald, are so well manu&ctured, that it is
often difficult to discriminate the genuine fix>m the felse. The
following jrields the best imitation of Emerald : —
TREATISE ON GEMS. 83
1000 parts of discoloured strass,
8 parts of pure oxide of copper,
.02 " oxide of chrome.
An Emerald is said to have existed at the Chapel of our Lady
at Loretto, in Italy, larger than a man's head, and for which an
Englishman offered ninety thousand crowns.
The sultan of Onde, in the East Indies, is said to have given to
the king of England, among other presents, an Emerald of the
size of a hen's egg.
The treasury of Vienna is said to contain an Emerald of two
thousand two hundred and five carats, valued at three hundred
thousand crowns.
The most magnificent specimen of Emerald was presented to
the cathedral of Loretto, by one of the Spanish kings. It consists
of a mass of white quartz, thickly implanted with Emeralds, more
than an inch in diameter. An Emersdd belonging to the crown
of Russia, is noticed in the Memoires du regne de Catherine^
Imperatrice de Rtissie, as being of the size of a hen's egg. A
fine crystal in the matrix, is in the museum at Dresden, which I
examined in 1827.
YIII. (B.) BERYL, AaUAMARINE.
This gem was likewise known to the ancients, who considered
and described it as a sea-green precious stone, and called the yellow
varieties of this mineral the Chrysoberyl. It was used by the
Romans as ornaments for cups, also for cameos. The crystals of
the Beryl are six-sided, terminated by six-sided pyramids, they also
taper gradually from one end to the other ; the lateral faces are
striated ; the firacture is conchoidal or uneven; they are transparent
or translucent at the angles, with indistinct double refraction, and
vitreous lustre : the colours are green, bluish-green, yellowish-
green, or greenish-white; bluish, sky, smalts or indigo-blue; straw,
wax or honey-yellow ; all pale colours : specific gravity 2.67 to
2.71. According to its colour and transparency, it is designated
the common and precious Beryl : under the first are generally
comprised the greenish and blue varieties, which are also called the
Aquamarine, whereas the yellowish varieties are exclusively called
the Beryl, and are generally divided thus : —
1. Aquamarine, pure pale sky-blue.
84 TREATISE ON GEMS.
2. Siberian Aquamarine, pale greenish-yellow, of a vivid lustre,
faint colour.
3. Aquamarine Chrysolite, greeuish-yellow, and yellowish-green,
vivid lustre.
The Beryl belongs to the primitive formation, is found in quartz
veins and granite, (graphic granite,) and is associated with Garnets,
duartz, Chrysoberyl, Schorl, Topaz, &c. The most magnificent
Beryls come from Siberia and Rio de Janero, in Brazil, Aberdeen-
shire in Scotland, and Limoges, in France. The common and
translucent Beryl occurs all over the globe, and in the United
States in great abundance, where it is without mercantile value.
The granite rocks of New Hampshire, (at Acworth,) have brought
fourth gigantic Beryls, perfect six-sided crystals, three feet in length
and four feet in circumference, and weighing upwards of three
hundred pounds, and some with a distinct termination of the
crystals. Specimens of this description may be seen in the collec-
tion of the Lyceum of Natural History, New York, in Mr.
Gilmore's collection at Baltimore, and in the author's collection.
Large quantities of Beryl crystals have also been found in Chester
county, Pensylvania.
The Beryl is cut on a leaden plate with emery, and polished
with rotten-stone on a tin plate, and generally of the brilliant cut,
on account of its not possessing much lustre in the interior.
The foil that is required in mounting, depends upon the colour
of the stone ; the greenish variety, for instance, is set with a
greenish-blue foil, the pale is set in a black ground, like the
Diamond, or on a silvery foil.
» Beryl is employed in jewellery for rings, pins, ear-drops, seals,
&c. : but on account of its softness, it is rendered less lasting, and,
as by wearing, it loses all its beauty, it does not command a high
price in market, being much below that of the Emerald.
A Beryl of a carat, avarages about one dollar and fifty cents,
and the price increases in the same ratio with the number of
carats. The Beryl is subject to such &.ults as spots, feathers, and
fissures.
For the Beryl, is sometimes substituted Chrysolite, which is
softer, however ; it is also imitated by paste, which is likewise
softer than Beryl.
One of the largest transparent Beryls, weighing five hundred
TREATISE ON GEMS. 85
and ninety-five carats, was once in the possession of a mineralogist
at Vienna. In 1811, a Beryl of fifteen pounds and one of four
pounds, pure, were discovered in Brazil. In 1S25, a beautiful
rounded Brazilian Beryl, of four pounds weight, was offered for
sale for six hundred pounds sterling.
Mawe describes a pure transparent Beryl altogether free of
faults, seven inches long and three quarters of an inch thick.
IX. ZIRCON.
Zircon and Hyacinth were formerly separated, until the improve-
ment in chemical analysis, which proved the same constituents to
exist in both, particularly the Zirconia, a pecuUar earth : they
have, therefore, ever since been considered as two varieties of one
and the same mineral. Zircon is also called Jargon, and this
name is either of Ceylonese or French origin. The ancients
considered the Hyacinth as that gem which is now known by the
name of Carbuncle, and meant by their true Hyacinth a dark
Amethyst. The Zircon was formerly used as a celebrated
medicine.
The Zircon crystallizes in four-sided prisms, terminated by
four-sided pyramids, with various modifications ; the crystals are
either smooth, rough, or uneven ; it occurs likewise in rounded
pebbles ; it is transparent and translucent ; possesses double refrac-
tion in a great degree; and has a vivid vitreous lustre, approaching
sometimes to adamantine. Colour, from hyacinth-red to yellow
and brown ; also, red, gray, white, brown, and greenish-gray. It
scratches, tolerably, quartz, but is attacked by the Topaz; its
streak yields a white powder ; specific gravity is 4.41 to 4.60 ; it
becomes electric by friction ; is infusible before the blowpipe, but
loses its colour at a low heat: the yellowish-brown, however,
becomes redder ; acids do not act upon it. Its chemical constitu-
ents are Zirconia and Silica, with about two per cent, oxide of
iron, which is the colouring principle.
1st The Zircon, called by the jewellers Ceylonian Zircon, fire-
red, yellow, yellowish-green, and gray.
2d. The Hyacinth is called by the jewellers the Oriental
Hyacinth, which is of a hyacinth-red, deep red, with a touch of
the brown, and sometimes orange-yellow colour. The Zircon
occurs in {ttimitive rocksi and forms a part of the Zircon Sienite
86 TREATISE ON GEMS.
of Norway and other countries. It is also found in gneiss,
granite, amygdaloid, and basalt. It is likewise found in the beds
of rivers ; and there are localities in Ceylon, Pegu, Madras, France,
Bohemia, Saxony, Italy, Siberia, Scotland, the Canadas, North
Carolina, <fcc.
The Zircon is cut with diamond-powder, or emery on a copper
wheel ; and is polished with rotten-stone on a tin plate, and
generally is cut in the rose, table, or thick-stone, and sometimes
the brilliant form. The foil generally used in mounting, is that
corresponding to its colour ; or it is mounted in a black ground.
If the Zircon is calcined in a crucible filled with lime, it loses its
colour almost entirely, and has then the appearance of a pale
straw-yellow Diamond, for which it may also be substituted. It
is employed in jewellery for rings, breast-pins, and ear-rings, or
for ornamenting watch-cases and snuff-boxes ; also for jewelling
watches and for supporting fine balances. The value of the
Zircon depends principally upon the purity of the colour, and that
of the Hyacinth is preferable to that of the Zircon : a carat of the
first is worth from fifteen to twenty dollars. The Zircon is
imitated with pastes, which may easily be detected by their lustre,
hardness and specific gravity ; likewise the burnt Topaz may be
substituted for it.
X. GARNET.
The Garnet was well known to the ancients, who considered
the Carbuncle as the same mineral, representing the whole species.
It was found among the ruins of old Rome in a variety of cut
forms. But the name Garnet is of modern origin, and probably
was bestowed on this mineral from being found mostly in grains.
The Garnet crystallizes in dodecahedral forms, with many modi-
fications ; the crystals are sometimes flattened into tables ; it is also
found in round angular grains, and massive; the structure is
imperfectly lamellar ; firacture, more or less conchoidal, sometimes
uneven and brittle ; lustre, shining vitreous ; it is transparent and
translucent; the colour is blood, cherry, or brownish-red, but
almost invariably mixed with a violet or blue tinge ; sometimes,
however, we find the Garnet of a yellow, green, brown, or black
colour.
The red Garnet scratches quarts faintly, but is attacked by
TREATISE ON GEMS. 87
Topaz, and even by the file ; its powder is reddish-green ; specific
gravity is fi'om 4 to 4.03 ; it becomes electric by firiction ; heated
by itself, the Garnet grows darker, but resumes its colour when
cooled; it fuses before the blowpipe into a black pebble. Its
chemical constituents are silica, alumina, and the protoxides of
iron and manganese.
The Garnet has its names according to the different shadings of
colour : —
1st. Syrian Garnet, which is also called the Oriental and
precious Garnet, Almandin, Carbuncle; this is of a blood-red,
dark crimson colour.
2d. Bohemian, or Ceylonese Garnet, called the Pyrope ; wine-
red, nearly orange-yellow, deep coloured.
3d. Vermeille or Aplome, having a deep shade of orange-yellow.
The red Garnet occurs in granite, gneiss, mica, talcose and
chlorite shists, and serpentine; also in loose crystals, small boulders,
grains, and in alluvion. It is found in Saxony, Bohemia, Tyrol,
Sjrria, Corinthia, Spain, Norway, Greenland, Ceylon, Hindostan,
and in the United States, viz : — New York, Connecticut, Massa-
chusetts, New Hampshire, and other places.
The Garnet is mostly obtained by digging and collecting the
alluvion ; such grains are more useful to the lapidary than those
occurring in the rocks. In Bohemia, where there is a considerable
trade in Garnets, they are separated fi'om the earth by levigation,
then assorted into difierent sizes, afterwards washed over again,
and assorted as to colour and quality, and according to the quantity
required for balancing a certain weight, such as half an ounce :
they are called 32, 40, 76, 100 to 40 ; very seldom they find them
16 — 20, weighing together half an ounce.
The larger Garnets are cut on the leaden wheel with emery, or
their own powder, and polished with rotten-stone or oil of vitriol,
on a tin plate, in the form of brilliants, roses, table-stones, or en
cabouchon, or with two rows of facets at the girdle ; and very often
Garnets are brighter, and more agreeable by excavating them
circularly on the bottom ; they are then called Garnet-cups. I
have in my possession several large excavated Garnets, and I saw
at Berlin, in 1828, such Garnets of two and three inches size.
Fine Garnets are set a jour^ others are set with a gold or violet
foil at the base. Smaller Garnets are wrought on a large scale in
88 TREATISE ON GEMS.
manufactories for that purpose. They are perforated with the
Diamond, by means first of a small point, and then of a larger,
and at last a finer point ; they may perforate daily one hundred
and fifty Garnets.
The first Garnets are cut in Brilliant form, and with regular
fecets, on a plate of fine sand-stone, with sweet oil and emery.
One man can finish thirty such Garnets in one day. The polish-
ing on wooden or leaden plates, with rotten-stone or oil of vitriol, is
performed by women and children. More than twenty thousand
Garnets are yearly carried to market fi-om a single manufactory.
Garnets are much worn in jewellery, as rings, breast-pins, ear-
rings, necklaces ; and sometimes snuff-boxes are cut out of the
larger ones from Greenland, Syria, or Tyrol ; the inferior pieces,
unfit for cutting, are calcined and reduced to powder, and employed
as material for polishing other gems.
The value of Garnets is determined by their degree of perfection,
as well as colour, purity, and size. On account of their peculiarly
deep colour, they are to be cut very thin ; and all such Garnets as
retain their fine colour, without being cut too thin, are held in high
estimation, and stand in value near the Sapphire. A Syrian Garnet
eight and a half lines long, and six and a half lines broad, and
cut octangular, was sold at the auction of the Marquis de Dree for
three thousand five hundred and fifty francs. A fire-red oval
Ceylonese Garnet, eleven lines long and seven broad, was sold for
one thousand and three fi'ancs. They are generally sold by the
pound, holding from sixty to four hundred, valued at about eight
to ten dollars per pound. But a set of one thousand of the best
selected Garnets, well cut, is sold at about sixty dollars. The
Garnet is harder than the Idocrase, and the oxide of tin ; but the
latter is heavier.
The Garnet is very well imitated by pastes, which are, however,
softer and lighter, and differ in many other respects.
The following composition yields a superior imitation of the
Syrian Garnet : —
To 1000 parts strass, add
600 " glass of antimony,
4 ^ cassius purjde,
4 <' oxide of manganese.
TREATISE ON QEMS. 89
XL ESSONITE, CINNAMON-STONE.
This gem was formerly considered identical with the Hyacinth^
under which name it passes yet in commerce, and among the
manufacturing jewellers ; and in France it is called Hyacinth de
Ceylon ] it also is called in mineralogical works Cannel or Cinna-
mon-stone, which name it received from the Dutch gem-dealersi
on account of its resemblance to the oil of cinnamon. Werner
was the first who gave this stone the above name.
Essonite occurs in crystals and grains ; its fracture is conchoidal
and uneven ; it is transparent and translucent ; has simple refrac-
tion of light ; the lustre is between vitreous and resinous ; its colour
is deep-red, hyacinth-red, and orange-yellow ; it scratches glass and
quartz indifferently, but is attacked by Topaz ; its powder is white;
specific gravity is 3.5 to 3.6 ; it becomes electric by rubbing ; acts
sometimes on the magnetic needle ; fuses easily befoi^ the blowpipe
into a dear greenish glass ; borax and acids do no afiect it.
Essonite is found in the sand of rivers, and in the primitive rocks
of Ceylon ; also in Scotland.
It is treated like the Garnet, by being cut on a copper plate with
emery, and polished on a tin wheel with rottenstone. It also
receives the form of other gems, and when set, it is mounted with
a foil answering to its colour.
It is used for rings and breast-pins. Essonite is distinguished
irom the Zircon by its less hardness, smaHer specific gravity,
•diminished lustre, and simple refraction of hght. Garnet is heavier
and Idocrase is lighter than Essonite.
Xn. TOURMALINE.
This mineral is as yet very little known among jeweDers, and
the trade in general, although it has been in commerce for a num-
ber of years past, but under other names, such as Red Tourmaline,
or the Siberite, brought from Siberia, and sold in the trade as
Oriental Ruby.
The Tourmaline was first introduced as a gem by the Dutch,
who imported it from Ceylon. The Tourmaline occurs in crystals
and crystalline masses, and its forms are six — nine and twelve-
sided prisms, with various truncations and terminations, which
commonly differ in the number and size of the faces at the two
ends. The crystals are long, striated and complete ; or aggregate^
M
90 TREATISE ON GEMS.
into irregular masses ; the fracture is conchoidal and uDeven, semi-
transpareat to cpaque. It has a double refraction of light, which,
however, is only visible in small pieces ; it has a vitreous lusire ;
the colours are blue, red, green, and brown, of different shades.
Several colours may often be observed in one and the same crystal ;
as, for instance, in the Rubellite from Paris, in Maine, and Ches-
terfield, Massachusetts, enclosed by the green Tourmaline ; and
the colour often varies in its different layers.
Tourmaline scratches glass sliglitly, but is scratched by Topaz ;
its powder is white ; its specific gravity is 3.0 to 3.3 ; it becomes
electric by rubbing, that end having the greatest number of faces
being positive, the other negative. Before the blowpipe, it intu-
mesces more or less, does not fxise, but vitrifies on the edges ; turns
green, then yellow, then red, then milk-while, then blue, and then
b!ack. Borax dissolves it pretty easily into a clear bead. The
chemical composition of Tourmalines varies greatly : they are
composed of alumine, silica, oxide of iron, oxide of manganese,
and boracic acid ; those from different localities contain, either
potash, soda, lithia, or calcia. The following are the different
varieties, not including,- however, the white, yellow, and black
Tourmaline or shorl, they not being used as gems.
1. Siberian Tourmaline, (Siberite, Rubellite, Apyrite,) which is
of a carmine or hyacintli-red, purple or rose-red, passing into violet ;
sometimes, by looking through in one direction, the red colour
changes into a blue colour : —
2. Indicolite, (Brazilian Sapphire,) of an indigo, lazulite, or
Prussian-blue colour.
3. Brazilian Tourmaline, (Brazilian Emerald,) of a grass-green
or olive-green colour.
4. Ceylonian Tourmaline, (Ceylon Chrysolite,) of a greenish-
yellow colour.
6. Electric Shorl, of a yellowish, reddish, liver or blackish-brown
colour.
The Tourmaline occurs in rocks, such as granite in layers and
gangues and in boulders ; it also occurs in the beds of rivers, and
tlie localities are Siberia, St. Gothard, Ceylon, Brazil, Sweden,
Saxony, Moravia. In the United States, Tourmalines are abundant,
but there are very few localities of the better varieties, such as at
f^aris in Maine, and Chesterfield ajid Goshen ia Massachusetts.
TREATISE CJN GEMS. 91
The Tourmaline is cut on a brass or leaden wheel with emery,
and polished with rottenstone on a tin plate ; it receives various
forms, such as the step and table-cut. If of a pure colour, it is set
a jour J otherwise with a foil corresponding to its colour ; but the
Electric Sborl is sometimes set so that it can be removed from
its mounting in order to perform experiments with. The value of
the Tourmaline depends upon its colour, purity, and size. The
Siberite and Rubellite stand highest in estimation. A Siberite, as
large as five lines, is worth about an hundred and fifty dollars ;
and one of four to twelve lines, good colour and pure, is worth
^bout fifteen hundred dollars. The Rubellite from Paris, Maine,
has become very rare, and it is much to be regretted that no more
attention is paid to obtaining a fresh supply, as the crystals are of
an exceedingly fine purple colour, and perfectly transparent. I
have a few polished Rubellites and green Tourmalines, in my
cabinet, which I value equally as high as any gems.
The dark-green Tourmalines six lines long and four broad, are
sold in Paris for eighty francs, and the light green, of the same
size, for forty francs. The most splendid Siberite is at the British
Museum, having been presented by the king of Ava to Colonel
Symes ; it is valued at one thousand pounds steding.
Tourmalines may at all times be readily distinguished from
other gems or pastes, which are sometimes substituted for them,
by their property of assuming polaric electricity after being heated.
aUARTZ.
This mineral is diffused* all over the globe. Its varieties are
very numerous, and many of them are employed in jewellery, and
for divers ornamental purposes. It occurs massive, in concretions,
in confused crystalline masses, and in crystals, of which the form
is the six-sided prism, terminated by six-sided pyramids ; also, the
dodecahedron, or double six-sided pyramid. Quartz scratches
glass and Felspar, but is attacked by Topaz. Its hardness is 7.0,.
and its specific gravity, 2.6 to 2.7 ; it is by itself transparent, and
possesses a vitreous lustre; becomes electric by rubbing \ is infusible
before the blow-pipe. Acids, except the fiuorib acid, do not act
upon it Silica is the only essential component part of quartz :
but some varieties contain iron, alumine or liihe.
92 TREATISE ON GEMS.
Xra. (A.) ROCK CRYSTAL.
This mineral was known in early ages. It was highly esteemed
by the Greeks on account of its purity and very regular formatioik
Theophrastes states that it was cut principally as seals, and the
ancients made great use of it for ornaments, particularly before
' the art of making glass had reached much perfection. Among
the many vessels which were cut in the form of cups, vases, d&c,
were two fine bowls and chalices in the possession of the tyrant
Nero, who had purchased them at a large sum. The Rock
Crystal was also used as a medicine.
It is found crystallized, in the primitive form, which is the
rhomboid, extended to a six-sided prism, and in a great variety of
forms and modifications, such as with a truncation or replacement
of the edges, or solid angles, &c. It is frequently found in groups,
also in the cavities of other minerals, or in incrustations, as small,
but very perfect crystals, the pyramidal terminations of which
have a high polish, and the specimen appearing as if it was
studded with gems. Many specimens of this description were
brought from Vermont but a few years ago, and were eagerly
purchased by the jewellers of this city for rings, ear-rings, and
breast-pins. Rock Crystal has a conchoidal fracture; is trans-
lucent and transparent ; possesses a double refraction of light ;
a perfect vitreous lustre ; is limpid, white, brown, black or yellow ;
scratches glass; specific gravity, 2.65. The electricity acquired
by rubbing lasts for thirty minutes. Before the blow-pipe, when
coloured, it is made limpid. The following varieties of it are
made known by their names and characters : —
1. The Pseudo Diamond, (Bohemian or occidental Diamond,)
which is the limpid, colourless Rock Crystal, cut and polished.
2. The Iridescent duartz is that variety of Rock Crystal, the
interior of which is replete with fissures and cracks, so that the
refraction of the rays of light produce the rainbow colours.
3. Citron, (Bohemian Topaz, Occidental Topaz, yellow Quartz,
Scotch Pebble,) which is of a pale, ochry, gold, white, lemon-
yellow or brownish-yellow colour. The false Cairngouram of
Brazil is a beautiful variety of yellow duartz.
4. Smoky Topaz, (Cairngouram or true Scotch Pebble, brown
duartz, smoky quartz,) is of a smoky or brown colour.
& TdovUmpiuof a charcoal black or brownish-Uack colour.
TREATISE ON GEMS 93
6. Hair or Needlestone, or such Rock Crystal as has, in its inte-
rior, foreign substances, as rutil, (red oxide of Titanium,) manga-
nese, iron, chlorite, amianthus or asbestos ; when the stone is so
cut as to represent the hair or needles in an upright position, they
are called either Yenus' hair {cheveux de Venus) or love's arrows
{Jleches cPamaur.)
Rock Crystal occurs in gangues, rock cavities in the oldest
geological formations ; it is also occasionally found in some modern
rocks.
The principal localities are the highlands of Tyrol and Switz-
erland, Madagascar, Dauphiny, Cornwall, - Hungary, Scotland,
Ceylon, aud Siberia ; in the Uni'.ed States, on the islands of Lake
George and at Trenton Falls, in the State of New York, very
perfect and completely terminated transparent crystals are found,
with their endless modifications ; some of them five inches long,
and some containing drops of water. It is also found in Wind-
ham, Vermont, where the drusy variety occurs, which is extremely
beautiful and of variegated colours. About two years ago, it had
a great many admirers, and was quite generally worn in brooches,
rings, &c. It is also found in Maryland, Massachusetts, and on
the Catskill mountains.
It is obtained in Switzerland and ^me other countries by
raining after it ; those cavities geologically or mechaj|kally ti-aced
by the veins from the duaA^ veins, are sounded oy them in
granite veins or other rocRs by means of instmments, aifll when
hollow, extensive preparations are made for procuring the whole
produce of the cavities, which sometimes amount to several tons.
It is likewise procured from the sand of rivers, and it passes then
under the name of Flints ; also in gangues or veins of other
minerals. The smaller and clearer transparent ones are generally
employed in jewellery and for ornaments ; but the larger speci-
mens are first assorted and then split or cleaned, and the smaller
pieces are sawed through with a copper wire, emery and oil, into
the desired sizes, when they are ready for being cut on copper or
leaden discs, with emery and water, and polished on tin plates
with rotten-stone, putty, bole, or other fine powder; or they may
be polished on wooden wheels, lined with fur gr leather. The
forms which they generally receive from the lapidary, are the
brilliant, rosei <x taUe. The Irideaceoi CLuartz, and the Hair or
94 TREATISE ON GEMS.
Needlestones, arc only cut concave. Those specimenis that have
a full pure wine-yellow colour, are best cut in steps. When
mounted, they are either a jour, or with a black foil. Those
which are spotted or of an irregular colour, may be discoloured by
careful calcination in crucibles, with lime, sand, or pearlash, which
process likewise increases the lustre. The crystal may be bored
with a diamond point, also engraved, and figures may be etched
in it by means of fluoric acid. It is mostly used for pins and rings;
also, for the base of the doublets ; likewise, for a very great variety of
ornaments, such as seals, gems, snuff-boxes, cane-heads, &c. :
likewise, for imitating the real gems, by being coloured and imme-
diately immersed in a solution of colouring water, whereby the
colour is very closely imitated. It is moreover the base of all the
pastes or strass.
Its value is by no means so high as formerly, when the demand
for it was great for setting in buckles, buttons, &c. Articles made
of large pieces of it, or those containing slender needles, hair, moss,
or other incrustation, or imitation of other substances, are yet
somewhat esteemed. In their natural state, if quite clear, as they
are received from Madagascar, Switzerland, and Brazil, they are
sold for from one to ten dollara per pound ; but when cut for seal-
stones, or bi-east-pins, they are sold mostly by the jewellers of this
country, a'^jyhite Topaz, and command a fair price. Well-cut
seal-stcmes are sold at from five to twej^y dollars. Those of the
brilliant-cut are sold from fifty cents to a dollar a piece. The
largest Rock Crystal is said to be in the collection of M. Rafisiellii
artist at Rome, and a large candelabra of Iridescent Quartz, in
the Vatican. The proprietors of the American Museum of this
city, can boast of having one of the largest specimens of Rock
Crystal from Brazil. It weighs two hundred and twelve pounds,
is two feet and a half high, and one foot in diameter, and is a
perfect six-sided prism.
Rock Crystal may be easily distinguished from white paste,
called strass, as the latter is heavier on account of the metallic
oxides contained in the composition.
XIV. (B.) AMETHYST.
This g^m has been known since the earliest ages of Greece
and Rome ; the name is of Greek mgin. Its cdoar is considered
TREATISE ON GEMS. 95
that of new wine. The ancients believed that wine drank from
an Amethyst cup would not intoxicate ; hence its name, expressive
of that belief. This name occurs in Scripture, being that of the
ninth stone in order on the high-priest's breast-plate of judgi^ient,
wnth the name Issachar engraved thereon. Amethyst was always
used for engraving. The bust of Trojan, in the Royal Library
at Paris, and the AppoUo Belvideie, the F^arnese Hercules, and ihfe
groups of Laocoon, are splendid specimens of it. It^occurs
massive in boulders, or in hexahedral prismatic crystafs, rormi-
nated by hexahedral pyramids. Its crystals are rarely as distinct
as those of quartz, being, for the most part, laterally aggregated by
the whole prism, the terminal pyramids alone being separated
from each other ; its fracture is from conchoidal to splintiy ; it \s
transparent to translucent ; of a vitreous lustre ; colour, of a high
and dark violet-blue, and from its richest tinge to almost colourless
on one and the same specimen. It scratches white glass, gives
fire with steel, but yields to the file. Its specific gravity, 2.75 ;
becomes electric by mbbing, which lasts, however, but half an
hour. Before the blowpipe, it loses its colour. Its component
parts are pure quartz, coloured by manganese and iron. It occurs
in veins of the older formation?, and studding the interior of agate
balls or geodes in the amygdaloid and trapp rocks of Hungary,
Silesia, Saxony, Tyrol, Oberstein, and as boulders of splendid
specimens in Ceylon, Sibeiia, and Brazil. It is wrought in the
same manner as Rock Ciystal, being cut on a ccpper wh^l with
etnery, and poli;jhed on a tin plate with^ rotten-stoqe. In order to
raise its lustre, many faces, and v^ry frequently those of a rose*
cliamond, are given tx) it in cutting. It is sometimes cut in the
form of a brilliant, and when set, it is supplied wnth a blue or
red foU, provided the Amethyst is pale, for the derp-coloured ones
^o not require any artificial assistance. It is used in alnio^t every
description of jewellery, such as rings, ear-rings, and breast-pins ;
but to its best and most showy advantage, it is set in necklaces,
and is the only coloured gem which maybe worn with mount-
ing, an advantage which adds to its value. The Amethyst is no
longer in such estimation as formerly, but the colour, when intense
and uniform, as also the size, contribute greatly to its value ; and
good wellTf^ Ametl^ystS) of oi^e c^rat, are worth from three to
five cblJ|ar^} $n4 ^ on ^) pyropoitioi^ t^ their si^ : au4 4>aiettiy9t
96 TREATISE ON GEMS.
fifteen lines long and eleven lines broad, exquisitely fine, was
valued at five hundred dollars.
The best Amethysts now in commerce come from Ceylon,
Siberia, and Brazil; the first are commonly called Oriental
Amethysts, which, however, must be carefully distinguished from a
much more valuable gem, the true Oriental Amethyst, which is
the violet Sapphire. I have in my collection a quantity of the
Brazj^lian Amethysts which are of an intense violet colour, and of
a very large size. »
Th^ Amethyst is often imitated with fluorspar or violet-blue
lime-spar ; both, however, are softer than Amethyst : the lime is
lighter, and the spar is heavier than Amethyst. But it is imitated
very strikingly by pastes, so that with great difiiculty the real is to
be distinguished from the imitation ; the latter, however, is some-
what heavier, on account of the metallic oxides contained in the
composition. The following is the best receipt for imitating the
Amethyst : add to
1000 parts of strass
8 " of oxide of manganese,
0.2 '^ purple of cassius, and
500 " oxide of cobalt.
One of the largest geodes of Amethyst was brought into England
in 1819, wejghing one hundred and fifty pounds ; it was two feet
long and fourteen inches broad, and contained the most magnifi-
cent crystals, which were of the deepest violet colour. On account
of having been set down at too low a price at the custom-house,
which was sixty-five pounds sterling, it was confiscated.
XV. (C.) COMMON aUARTZ.
But a few varieties of the common Quartz are used in jewellery,
which are : —
a. The Rose Quartz,
6. The Cat's-eye,
c. The Prase, and
d. The Avanturine.
a. ROSE aUARTZ.
This mineral generally occurs massive ; is but semi-transparent,,
and translucent on the edges ; has a vitreous lustre ; conchoidal
TREATISE on OEMS. 97
and splintry fracture ; is of a rose-red colour ; sometimes giving a
shine of mother-of-pearl. It scratches glass ; has a specific gravity
of 2.64 to 2.67 : its colour, which is derived from the oxide of
manganese, becomes paler before the blow-pipe.
Rose duartz occurs in gangues of granite and gneiss, particu-
larly fine in Sweden, Bavaria, Bohemia and Siberia ; also of a
beautiful dark colour in New Hampshire and Massachusetts.
Rose duartz is cut and polished for jewellery ; such as rings,
breast-pins and snuff-boxes ; it is cut on a copper wheel with
emery, and is polished with rotten-stone and putty, on a tid plate,
receiving the form of a cabochon or table, and when set requires
a foil, coloured by carmine or solution of gold, as it &des
when exposed a long time to the light. The Rose duartz is not
held in great estimation ; the colour as well as the lustre may be
resuscitated in laded Rose duartz by being left for some time in a
moist place.
A vase of Rose duartz was in the possession of the Marquis^ de
Dr^e, , nine inches high and two inches in diameter.
XVI. (C. 6.) CAT'S-EYE.
The name of this mineral is derived from the peculiar play of
light perceptible on its surface, by which it resembles the rays of
light in the eyes of a cat ; it is not ascertained whether the ancients
knew the same, and whether it was comprised in their Asterias ;
but it is well known that Cat's-eye is in high estimation among
the Malabars and Moors ; and it is worn through the whole East,
where it is employed as an amulet, being believed to possess the
virtue of enriching the wearer.
Cat's-eye occurs massive, and in more or less roundish pieces ;
has a conchoidal fracture ; is translucent and transparent some-
times on one end ; it has a shining lustre, between vitreous and
resinous ; gray and brown, green, red, and yellow colour ; it pre-
sents a peculiar floating light, which is particularly visible if cut
in high cabochon, as it usually is when brought to market; it
scratches glass ; has a specific gravity of 2.56 to 2.73, and contains,
besides silica, some alumina, calcia, and oxide of iron, as 95 silex,
1.75 alumina, 1.50 lime, and 0.26 oxide of iron. In many speci-
mens, thei^ may be observed small parallel white fibres, which are
supposed to be die cause of its peculiar play of light ; but the semi-
N
98 TREATISE ON GEMS.
transparent varieties, which are equally chatoyant as the more
opaque ones, present no such appearance. This leads to the con-
clusion that amianthus in its finest fibres occasions the phenome-
non, and the chemical analysis of the latter corrAponds with the
additional constituents of the Cat's-eye. By exposure to a strong
heat, it loses its lustre and transparency; and, in small fragments,
is fusible before the blow-pipe. Cat's-eye is found in the fragments
of gangues and boulders, of very small size, never larger than a
hazel-nut, in Ceylon, on the coast of Malabar, in the Hartz moun-
tains, Bavaria, and in this country, (in Vermont, New- York, &c,)
Ceylon, where the finest Cat's-eyes are found, sends them abroad
already cut and polished en cabochon ; but very often they are
cut over again on a copper wheel, with emery, and polished on a
tin plate ; it receives in setting a gold foil. The value depends
principally upon its intrinsic properties, size, colour, and degree of
play of light. Of the nearly opaque varieties, the red and the
almost white are the most esteemed, and such are sold usually from
ten to twenty dollars ; and a stone of the size of a square inch,
and otherwise perfect in its properties, is worth from eighty to one
hundred dollars.
In the imperial cabinet of Vienna, a five-inch long Cat's-eyc, of
a yellowish-brown colour, may be seen.
XVII. (C. c.) PRASE.
This mineral is mentioned by Pliny ; but it is not certain whether
he meant the same substance that we do : more probably he alluded
to the Emerald ; for the same mineral is at the present time called
the Emerald Mother or Matrix by the jewellers. Prase occurs mas-
sive and crystallized ; it has a conchoidal fracture ; is translucent
on the edges ; between vitreous and resinous in lustre ; and of a
garlic-green colour, the cause of which is, that acUnolite is inter-
mixed with the silex. It scratches glass, has a specific gravity of
2.66 to 2.88, and is composed of silex and alumina, oxides of iron
and manganese. It is found in Saxony, Tyrol, Styria, Hartz, and
the island of Elba. It is used for rings and pins ; also, for snuff*
boxes and other jewellery, and is cut en cabochon, and set with a
gold foil at the base, by which its colour is heightened, and ren-
dered more agreeable. It is used in mosaic works, as in the foliage,
and Ukewise in the mounting of Rubies, in order to raise tl^ir
TREATISE ON GEMS. 99
colour. Prase does not stand in great estimation ; for although it
assumes a very good polish, it loses the same on long exposure to
the air, aivi grows spotty.
XVIII. (C. d.) AVANTURINE.
This mineral received its name from bearing a resemblance to a
glass paste, formerly manufactured in Italy. It is a brown or red
quartz, which is massive and translucent, or opaque ; it has a resi-
nous lustre, and its fracttire is splintry and uneven : it is penetrated
with gold or brass^yellow glistening fissures, caused by the refrac-
tion of light, or by innumerable mica leaves. It scratches white
f^bukBf has a specific gravity of 2.64 to 2.68 : silex. with some alu-
mipa and water, are its constituents.
The Avanturine is found in the Uralian mountains, Styxia, near
Madrid, Nantes, Scotland, &c. It is used for ring-stones, ear-rings,
and snqfi'-boxes. It is cut on a copper wheel, with emery, and
polished with rotten-stone on a tin plate ; it is cut semi-lenticular
or oval, does not take easily a ^ood polish, but may be improved by
rubbing the stone with oil of almonds. The value of the Avan-
turine is much depreciated of late, and its imitation of glass paste,
which is generally called the Goldstoncj is by far superior to the
real stone, which has nothing but hardness in its favour. This
paste is manufactured in great quantities in France, by throwing
the finest impcUpable powdered brass into a quantity of colourless
strass, or into a composition of
105 parts quartz,
85 " purified potash,
230 " tin and lead alloy,
50 " brass powder.
XIX. (D.) JASPER.
This mineral is of oriental origin, and is very often mentioned in
the Bible. It was the sixth stone in the plate of the high-priest.
Jasper was well known to the Greeks and Romans ; and according
to Pliny, who has described several varieties, the best came from
Scythia, Cypria, and Egypt. The lapidaries formerly made use
of it in their works, particularly the Egyptian Jasper, which afforded
them abundant materiel ; the column of Memnon and the founda-
tion of the column of Pompey were constructed of it ; and we find
k
100 TREATISE ON OEMS.
daily among the excavations of Herculaneum and Pompeii frag-
ments of ruins composed of Egyptian Jasper.
Jasper occurs in enormous masses ; has a conchoidal fracture,
is opaque ; its lustre is slightly resinous, like wax, often dull ; it is
of white, red, yellow, green, blue, brown, and black colours. It
scratches glass, but jrields to rock crystal. Its specific gravity is
J8.31 to 2.67.
It is found in gangues, more seldom in strata^ in Egypt, Bohe-
mia, Saxony, Tyrol, Hungary, France, Italy, Spain, Siberia, and
in the United States, principadly in Florida, North Carolina, Mas-
sachusetts, &c. ; also, in Nova Scotia.
According to their varieties, which are very numerous, that is in
colour and structure, they receive their names ; but they may still
be classified into the following two divisions : —
a, Egyptian Jasper^ (Egyptian Pebble,) which occurs in sphe-
roidal pieces, of a gray-brown or red colour, and the form of which
may mostly be cut and pdished in annular representations around
its centre. It is found in Baden, Upper Egypt, and other places ;
among the pebbles of the river Nile it is frequently discovered;
and in the year 1714, it was found near the village of Incheric by
Paul Lucas. .
ft, Ribband or Striped Spar, It occurs in masses, with nearly
conchoidal fracture, around which parallel straight or twisted stripes
of a gray, green, yellow, red, or brown colour may be perceived : it
is principally found in Siberia, the East Indies, Corsica, Tyrol, and
the Hartz mountains ; also, some of the West India islands produce
most splendid specunens.
Jasper is principally used for seals, snuff-boxes, vases, table-plates,
and fer some architectural purposes.
When in lumps, it is divided by means of copper saws and fine
sand, and then cut on copper or leaden wheels with emery, and
polished oil tin pbiti^ with rotten-stone, colcothar, or charcoal ; or
it may fijrst be polished on wood with pumice-stone, and lastly on
a tin {date with rotten-stone and water.
The yellow Jasper is often employed in mosaic works in Italy,
and the striped Jasper as cameos. The Jasper has no great value
in trade, excepting it be of exquisite quality, and fine objects be
made of the same. It generally commands the best price in China,
vfJBKae the epiperor has a seal cut of it A vase of red Jasper, with
TREATISE ON GEMS. 101
white veins, and one of black Jasper, with yellow veins, may be
seen in the Vatican. Chatouilles and other boxes of considerable
- , • •
size are frequently found in the jewellery stores of France, England,
and the United States. ^-' \
- • ••
XX. (E.) HORNSTONE. \\.
Hornstone occurs massive, globular, stalactiform, and in pseudo^
morphous crystals of carbonate of lime, and also in the form of.
petrified wood, (wood-stone or agatized wood.) Its fracture is either
couchoidal or splintry ; it is opaque or transparent on the edges ;
has a dull or shining lustre ; deep gray, brown, red, yellow, or
green, and rarely a pure colour. Often it has several colours in one
and the same specimen, such as points, spots, and stripes. It
scratches glass, and has a specific gravity of 2.53 to 2.65.
It is mostly found in gangues of the older formation ; also, in the
old red sand-stones and alluvial formations ; in Bohemia, Saxony,
Sweden, Siberia, Hungary, and a number of other places ; in the
old red sand-stone of Thuringia. I have traced one stem of the
red agatized wood eighteen feet in length and two feet in diameter.
The price of Hornstone is very low ; it is used for snuff-boxes,
seals, crosses, mortars, and principally as knife and fork handles.
It is now used by the silvor-smiths to mount butter and dessert
knives and forks, which are imported from Germany in consider-
able quantitnSir
CHALCEDONY.
XXI. (P.O.) CHALCEDONY.
This mineral was held in great estimation by the ancients, who
received their principal supplies from Egypt and other parts of
Africa. In Rome, much use was made of it for cameos, many
of which may yet be seen in collections. The inhabitants of
Iceland are likewise said to value it very highly, and to attribute
many medicinal properties to the same. It is found in crystals, such
as cubes, but mostly massive, botryoidal, stalactiform, globular, or
reniform, &c. The fi^cture is even, sometimes running into cou-
choidal or splintry ; it is semi-transparent or translucent, of little
lustre or dull ; of white, gray, blue, yellow, brown, or green coloun^
which are all of a light shade, and variously figured, strip^
spotted, &C.
«•
102 TREATISE ON GEMS.
* • »
It scraickoB* white glass, and has a specific gravity of 2.58 to
2.66. ^ {|t b distinguished into the following varieties, viz : —
1.^ Cl^ttlcedony proper, or Chalcedony x, wherein white and gray
stripes* alternate with each other.
' . .2. Mocha or Tree stones are such Chalcedonies as display black,
.))roii^n, or red dendrolical figures.
•*/•'* "S. Rainbow or Agate Chalcedony, is Chalcedony of thin and
I. './.concentric structure, which, cut across and kept towards the light,
*/• .* displays an iridescence.
4. Cloudy Chalcedony, has a light gray and transparent base
with dark and cloudy spots.
5. Plasma, dark grass-green. This mineral was very often
employed by the ancients for cutting.
6. Semi-Carnelion or Ceregat, is generally called the yellow
Chalcedony.
7. Sapphirine, is the sky or sapphire blue Chaltedony.
8. St. Stephen's Stones, is the white Chalcedony with blood-red
spots.
There are many more varieties, and in my own collection I
have polished Chalcedonies, among which, perhaps, as many again
may be enumerated.
Chalcedony is found in gangues, and in the cavities of many
rocks, also in boulders and pebbles. Localities exist in Saxony,
Hungary, Faroe Islands, Ceylon, on the shores of the Nile, in
Nubia, Nova Scoda ; the United States, (in Connecticut, Massa-
chusetts, Pennsylvania, Ohio, New Jersey, Missouri, Florida,) and
in other countries ; but the best specimens are brought firom Ober-
stein, Iceland, and the Faroe Islands.
The finer specimens are emjdoyed in jewellery^ for rings, pins,
bracelets, necklaces and seals ; the more common for snuff-boxes,
vases, buttons, &c. The larger masses are cut by means of a
copper wire, with emery and oil on a copper wheel; they are
polished on a tin plate with rotten-stone, putty-powder and pumice-
stone. The cutting is generally done on a large scale, like that of
agate. Many are susceptR^le of receivaig figures artificially, by
means of the nitrate of silver. By Oriental Chalcedony is gene-
rally understood the better qualities ; those Chalcedonies of two
or three divisions, called Onyx, are used for cameos.
The value of the Chalcedony depends on. its quality, mdh as
TREATISE ON OEMS. 103
purity, colour, and the figures and drawings displayed on it ; and
among all the varieties of Chalcedony, the Mocha stone stands
the highest in price, and also the Onyx, which is principally
employed for cutting cameos, and according to its size, commands
a high or low price. Mocha stones are sold in France at from five
to eight francs. The cabinet of Dresden contains a plate of Onyx,
about three inches broad and long, which is estimated at twenty-
five thousand dollars.
XXII. (P. b.) CARNELION.
This stone was known to the ancients by the name of Sarda ;
which, according to some, is derived from a place in Lybia or
Sardinia, and according to others, firom the Arabic word sarda,
meaning yellow ; it has been employed very fi-equently for cutting
ihtaglios or has relief gems.
Carnelion occift massive or in febbles ; its fracture is conchoi-
dal ; lustre resineus ; it is semi-tranpiparent and translucent ; of a
blood-red and yellow-brown, and yellow colour ; frequently dark
at the outside, growing paler towards the inside ; the colours are
sometimes changing striated ; it scratches white glass, and has a
specific gravity of 2.59 to 2.63. There are two varieties known
by the lapidaries and jewellers which are better than the others ;
those having a pale colour or yellowish tinge, and those having a
dark-red colour ; the latter are in the highest estimation, and are
called by the French Cornalines de vieille roche.
Sardonyx is called a Carnelion, having as its principle colour
the dark-browH or orange-yellow, interchanged with layers of a
white colour.
Carnelion Onyx, has a blood-red base, marked with white stripes.
The finest Carnehons come from Siberia, India, Arabia, Nubia,
Surinam, Oberstein in Germany, and Tyrol ; they occur mostly
as pebbles or in cavities of rocks ; in the United States they are
found near Lake Superior, in Mistfoim, and Id Massachusetts.
The Carnelion is used for numerous articles in jewellery, such as
seals, rings, watch-keys, &c. ; it is cut on a leaden plate with
emerj^i and is polished on wood with pumice-stone, and obtains its
highest polish on a plate composed of lead and iin with rotten-
stone aod water. The form of its cutting is that of pavilion or
it0p-cot oa the upper part, and either quadrangular, hexagonal or
104 TREATISE ON GEMB.
octangular, or also round ; and for raising its lustre or colour it is
furnished with a silver or gold foil, or with a red paint on its base.
The colour of the Carnelion is also improved by calcination ; the
yellowish kind, for instance, by calcining it in a moderate heat
and cooling it slowly, may assume a good red colour. It is said
that the ancients boiled the Carnelion in honey in order to heighten
its colour. Coloured figures or drawings may successfuU be repre-
sented by a mixture of white-lead, •olcothar, or other metallic
oxides and gura-water, which is the material for drawing on it,
and by burning the same under a mufSe.
The faults of the Carnelion are fissures, unequal colour, and
flaws from other stones. The Carnelion is, on account of its
being less brittle, more useful for engraving and cutting cameos ;
and generally the white layers are used for the figures of the
cameos and the red for the base. Sometimes such Carnelions as are
cut with has relief objects, are fflled out with coloured strass ; and
we receive from India, very frequently, cameo^ with the most
singular drawings, and which are made by the inhabitants in the
following manner : the whole Carnelion is covered with carbonate
of soda, and then exposed to the fire for a few minutes, whereby a
strass is formed, which serves for cutting such figures upon.
The value of the Carnelion is much higher than any chalcedony,
but yet depends on all its qualities of colour, transparency, equal
division of colour, and freedom fi-om any faults, such as fissures,
clouds, dark spots, &c. For a perfect Sardonyx, a very high price
is generally given, particularly when the layers are very distinct
and run quite parallel, and are pretty thick, so that they are fit
fcr cutting cameos or intaglios. The blood-red is second in value,
and the pale-red, third ; but the cheapest are the yellowish, brownish,
or whitish kinds ; the prices vary from twenty dollars to twenty
cents per piece. There exists a cameo of Sardonyx, representing
the portrait of the celebrated father Fontanarosa, having its face
white, with the base, cap, and cloak black, so that it may distinctly
ehow the Dominican monk.
XXin. (G.) HELIOTROPE, BLOODSTONE.
This stone derives its name fix>m the Gi'eek language, having
been used in ancient times for observing the sun ; Pliny speaks,
likewise, of the Heliotrope. It occurs in massive and obtuse
TREATISE ON GEMS. 105
angular lumps, of a conchoidal fracture, is translucent on the edges,
of a resinous lustre, and leek-green colour, with red and yellow
spots. It scratches white glass, has a specific gravity of 2.61 to
2.63. The Heliotrope is found among amygdaloid, in Tyrd, in
the United States, (in New- York, near Troy,) Scottish Islandsi
Siberia, Faroe Islands, Egypt, Barbary, Tartary, &c. It is princi-
pally employed in rings and seals, watch-keys, snuff-boxes, and
other articles of jewellery ; also for sword and dagger handles, and
is wrought like Chalcedony, but sometimes cut on brass plates ;
its forms are various ; as en cabochon and pavilion.
The Heliotrope has been greatly admired in modem times ; its
price depends upon the colour and quantity of red spots contained
in the same. From one to twenty dollars is the usual price for
good and large specimens.
It is said that superstitious people in the middle ages valued the
Heliotrope, with many red spots, very highly, thinking that Christ's
Uood was diffused through the stone.
XXIII. (H.) AGATE.
This stone was well known to the ancients, and used for various
purposes of jewellery. In Rome, it was principally used for cutting
cameos from the striped kind, the onyx. It has also been worn as
an amulet, with different characters engraved on it. Its name is
derived from a river in Sicily, where the ancients procured it. The
Agate is a mixture of several species of quartz, which are com-
bined variously together ; Chalcedony or C^arnelion usually forms
the principal part, and is mixed with Hornstone, Jasper, Amethyst,
Quartz, Heliotrope, Cachelong and Flint ; and according to thk
predominating substances, it is sometimes called Chalcedony,
Jasper, or Carnelion Agate. Its colour, as well as its other
characters, depends upon the nature of the mixed parts ; likewise
its hardness; but it usually scratches white glass, and has a
specific gravity of 2.68 to 2.66 at the utmost.
According to the different figures represented in the Agate, it
receives its various names.
1st. Riband, or^ Striped Agate, representing layers variously
coloured, and alternating with one another. Onyx^ or Agate Onyx,
are such Agates as have the colours beautiful and distinct, and
whose layers run with the larger surfsuse in a parallel direetaon \
o
106 TREATISE ON GEMS.
whereas the common Riband Agates display their various layers
on the surface, without being parallel. If the stripes run together
around the centre, it is called the Circle Agate^ and if in the
same stone the centre shows more coloured spots, it is called the
Eye Agate, or Eyestone,
2d. Fortification Agate is that brownish Agate, the various
coloured stripes of which run in zig-zag, or irregular lines and
angles, representing the ground plan of fortifications.
3d. Rainbow Agate ; the curved stripes have the property of
displaying rainbow colours when held towards the sun, or candle-
light, and the more distinctly if the stone is cut very thin.
4th. The Cloud, Landscape, Dendritic, Figure, Moss, Punctated,
Star, Petrifaction, Shell, Coral, Tube, Fragment and Ruin Agates
are all the various forms in which the Agate is displayed, according
to its figure or drawing ; a Ruin or Fragment Agate may be
pasted together from the firagments of a common Riband Agate,
so as to make it represent old walls, whereby it receives the name
of Breccia Agate ; and sometimes the Rainbow Agate occurs in
connection with the Shell Agate, where the moss surrounding the
petrified shells forms the Rainbow Agate.
The Agate is found in gangues, on gneiss or porphjnry, and
amygdaloid ; also, as boulders and pebbles, in rivers, iac. It is
found in Baden, Oberstein, Saxony, Bohemia, Hungary, the Faroe
Islands, Siberia, the West Indies, and in the United States, (Massa-
chusetts, Rhode Island, New Jersey, Indiana, Missouri, Maryland,
Georgia.) Those occurring in amygdaloid are mostly in the form
of geodes or balls, hollow at the inside, and coated with quartz or
amethyst ; when the rock begins to disintegrate, these balls, becom-
ing loose, fall scattering around the soil, and are then collected by
persons who make it a business of either selling or cutting them.
The Agate is used, not only for various purposes of jewellery
and ornaments, such as seals, snuff-boxes, crosses, cases of various
descriptions, ear-drops, &c., but also for numerous other useful
purposes, on a large scale ; such as slabs, mortars, vases, instru-
ments, knife and fork handles, playballs, &c. The manu&ctur-
ing of them forms a considerable branch of industry in a part of
Germany. The Agate, after having been reduced to suitable
sized pieces, by means of a saw, chisel, or hammer, is then cut on
a copper wheel, by means of emery, powdered Garnet or Topaz,
TREATISE ON OEMS. 107
and is afterwards polished on a tin plate, with rottennstone, putty
or pumiceHstone.
Obersiein, a small place in Rhenish Bavaria, in the north of
Germany, has five large manufocturing establishments for the sole
purpose of cutting and polishing the common gems or semi-precious
stones ; and it is the only place where this branch of business is
carried to any great extent Twenty mills are constantly driven
by water, and more than one hundred thousand dollars worth of
work is turned out yearly for export ; a sum which is small in
comparison with the enormous quantity of goods manu&ctured
and set afloat, but pretty considerable for such places, where labour
is so cheap, and the best of workmen may be had for one dollar
and fifty cents per week. At Oberstein the business is divided into
two branches ; the one is devoted to the cutting and polishing of
the Agate, and the other to the boring ; and the workmen are
called the Agate lapidaries and the Agate borers. The cutting is
performed in the large Agate mills on sandstone ; each mill has
generally five large sandstones, five feet in diameter and fourteen
to fifteen inches in thickness, fastened upon a shaft, which causes
them to revolve vertically, and which are continually moistened
by a stream of water. The workman leans with his body on a
peculiar bench, the seat of which is called the cuirass, and with
his feet presses himself against a pole, whence he continually
pushes the larger lumps of the Agate towards the mill-stone ; this,
however, is often made so smooth, from the friction, that it is
necessary to make it rough by knocking it with a sharp hammer,
according to the kind of work, whether fine or coarse. They are
either pdished on sandstone or on wood, by means of fine clay (a
powdered chalk ; they are polished sometimes, also, on wooden
wheels, covered with lead or tin. Snuff-boxes and other articles of
Agate, which are hollow, are polished on smaller sandstone wheels,
which diminish in size as the work advances. Agates which
require to be bored, belong to a particular branch, distinct from the
other. The boring is performed by means of a Diamond point,
and as described by Mr. Mawe. The Onyx varieties are mostly
employed for cutting cameos, and are prepared there in such a
manner that the darker layer is cut for the base, and the lighter
for the intended objects.
Next to Oberstein, in Germany, there is in Siberia, at Kathe-
108 TREATISE ON OEMS.
rineburgh, the largest manufactory for grinding and polishing the
Agate and other gems. Many varieties of the Agate are used for
engraving other stones, and also for the Florentine or stone mosaic
work. Since the Agate has always been, and is yet, a £Bivourite
slone, it has been attempted to improve either its colour or other
external appearance by artificial or mechanical means ; these are
either by the use of metallic solutions or by boiling in oil of vitrioL
The colour has often been improved also by giving to the stone,
before it is polished, several strokes in succession, the small fissures
thereby produced, displaying an iridescence or some other phenom-
enon, if held towards the light ; this operation, however, may
easily be detected by wetting the stone, when the water, entering
into the fissures, will destroy the effect ; it will show itself again
when dry. On some Agates black and white layers are produced,
in order to use or sell them in the place of real onyx ; this opera*
tion is performed by the lapidaries, who boil certain varieties in oil
of vitriol, which turns some very soon into a black colour, and
lenders others clear or still paler ; tlie polished Agates are, however,
only used for this purpose, and the cause appears to lie in the oil
absorbed by them during the operation of polishing ; on which
account Agates are by some first boiled in oil before submitting
them to the operation of the oil of vitriol.
The value of the Agate, although much reduced in comparison
to former days, and a good deal depending upon the purity and
perfection of colour and peculiar figures, commands a pretty good
price in the market ; it is particularly the Onyx which is yet at
high sums, and on that account the same is imitated by pasting
thin plates of Chalcedony, Jasper, Agate, &c, together, and
making them by their different colours appear like real onyx ; this
deception may, however, be easily detected by putting it in hot
water, which disengages the plates one from another ; the Onyx
is likewise imitated by pastes, and very happily, but may readily
be distinguished from them by the hardness and other characters
prominent in the real stones.
The greatest collections of antique Onyxes, engraved as cameos
and intaglios, are in Vienna and Berlin ; in the first is to be seen the
apotheosis of Augustus, which is ten lines broad and six high, and
contains twenty perfect figures ; this was purchased by the Empe-
lor BAidolph al Fraokforton the Maine for fiftseo thousand ducats.
TREATISE ON GEMS 109
The celebrated cameo ia the Vatican Museum at Rome is of
Agate, and represents Augustus. Italy has always been the great
emporium for genuine antique Onyxes and cameos, and occasion-
ally we still behold fine specimens of art in the possession of
travellers coming from Europe. A very fine collection of antique
cameos and intaglios in precious gems and antique pastes ; like-
wise, cameos and intaglios of modern artists, I have seen in this
country, in the possession of Thomas G. Clemson, Esq., of Phila-
delphia.
I have in my collection a good Onyx of the Emperor Yitellius ;
a splendid cameo of Bacchus, of two and one-fourth inches long
and one half inch thick ; one of Anthony and Cleopatra ; also, a
splendid intaglio.
In Paris are several celebrated cameos, worthy the notice of tra-
vellers going to Europe : the Brunswick Vase, representing Ceres in
search of Proserpine ; Agrippina and her two children, composed
of two layers, brown and white ; the Quarrel of Minerva with
Neptune, which consists of thi^ee layers ; Venus on a sea-horse,
surrounded with Cupids, &c.
Some modern works of cameo, from the hand of the celebrated
Puckler, are in the collection of Robert Gilmore, Esq., at Baltimore,
and in that of W. J. Lane, Esq., of this city.
XXIV. (I.) CHRYSOPRASE.
The anciently this name designated a stone ^f a green colour,
with a yellowish tin^e ; but it is not certain whether that which
goes by this name, at the present day, is the same. We find, in
the fourteenth century, this stone used as ornaments in churches
and other places ; but it was not known by the above name until
1740, when it was discovered by a Prussian ofiicer in Silesia.
Frederick the Second ornamented his palace Sans Souci with this
mineral.
The common people of Silesia wear the Chrysoprase around the
neck, as a charm against pains.
Chrysoprase occurs massive and in plates ; the fi*acture is even
and splintry; it is translucent; lustre, resinous; sometimes dull
colour apple-green, grass-green, olive-green, and whitish-green. It
scratches while glass distinctly, but is not so hard as true Chalce-
dony. Specific^raArity is^2.5fi{ ii ia infiiaiblei be&oe the blow^pipe,
110 TREATISE ON OEMS.
but loses its colour when heated. It consists of silex with a little
carbonate of lime, aluranina, oxide of iron, and nickel ; its colour
is imparted by the latter substance. This mineral is found in the
Serpentine of Silesia ; also, in Siberia, and in the United States,
(in New-Hampshire.)
Chrysoprase is used in jewellery and for various ornamental pur-
poses, such as breast-pins, rings, bracelets, necklaces, seals, ice. ;
and the larger masses are used for snuff-boxes, cane-heads, table-
plates, &c. The cutting is pretty difficult, and the greatest care is
required for finishing the same with facets, as it is easily fissured :
it is done on tin or lead plates with emery, keeping the first con-
stantly wet with water ; it is polished on a tin plate with rotten-
stone, but the lapidary has always to be cautious not to let it
become hot, as it easily splinters, grows opaque and gray. The
usual coi is the table or en cabochon, with facets on the border ; in
setting, a foil of green satin is often used for a back, but when pure
«nd of good colour it is mounted a jour. Inferior specimens are
painted on the back with a mixture of verdigris, white-lead and
gum-mastic, or with sap-greeii.
The Chrysoprase loses its colour by wearing ; heat and sun-
light likewise cause it to fode, and render it dark and cloudy ; but
the colour may be restored by keeping it in a wet fx moist place,
such as a cellar, in wet cotton or sponge, or even by dipping it in a
solution of nitrate of nickel, which serves likewise to improve the
inferior qualities^ *
Very fine imitations in paste may be made by mixing
1000 parts of strass with
5 << of oxide of iron, and
8 <^ of oxide of nickel.
The Chrysoprase is subject to a great many faults, such as
fissures, either natural or received in cutting ; oily whitish spots,
pale gray flaws and stripes, and sometimes small grains of clay of
reddish colour intermixed in the intericnr of the stone ; but when
pure, the Chrysoprase has always been a great favourite. A good
seal or ring-stone may be worth from twenty-five to thirty dollars,
and smaller specimens from one to five dollars; The apple-green
variety is most valued, and a specimen one line long by one-half
broad, has been sold at from fifty to one hundrtti And fifly doOars.
At Paris, an ovat^Chr^rsoprase, eig^ lines long and seven lines
TREATISE ON GEMS. HI
broad, was sold for three hundred and ten francs. The price gene-
rally has decreased of late, on account of th6 great quantity cut
from the mines, which have recently been covered up, in order to
rai^e its value again. At the royal p^dace of Potsdam, in Prussia,
are two tables of Chrysoprase, the plates of which are three feet
long, two feet broad, and two inches thick.
XXT. CHRYSOLITE.
The name of this stone is of Grdek origin, and was well known
to the ancients, although it is undecided whether they understood
the same mineral by this name as we do at the present time, for
they make it in their writings to be either the Topaz or Goldstone,
or the transparent gold-ydlow stone.
The Chrysolite occurs in prismatic forms, generally a right prism
vnth rectangular bases ; also, in angular rounded crystalline grains
or massive ; the fracture is conchoidal ; it is transparent and trans-
lucent ; it possesses powerful double refracting power ; its lustre i0
vitreous and resinous; the lateral planes of the crystals are some*
times striated ; the colour is olive-green, turning to yellowish and
brownish ; it scratches glass indistinctly, and is attacked by Topaz ;
its specific gravity is 3.33 and 3.44 ; becomes electric by rubbing ;
is infusible by itself before the blow-pipe, but is dissolved into a
transparent pale-green bead with borax ; acids do not affect it ; it
consists of magnesia, silica, and oxide of iron. The Chrysolite is
found particularly in basalt, trap, green-stone, porphyry, and lava ;
sometimes in alluvial deposifes and the sands of rivers ; its principal
localities are Brazil, Upper Egypt, Isle of Bourbon, and Bohemia.
The Chrysolite is cut on a leaden wheel with emery, and is
polished on a tin plate with rotten-stone or oil of vitriol. Some-
times pale stones are finally polished with some olive oil, which
raises the colour considerably: this last operation is applied to restore
its lustre, after the Chrysolite becomes dull by wearing. The form
is that of a rose or table-cut ; also, en pavilion ; and when set, gold
foil is used for its base: the pale-coloured Chrysolites look well with
a green-coloured copper foU; dark Chrysolites maybe rendered
clearer by a careful calcination.
The Chrysolite is used for rings and pinsj but does not stand in
high estimatknii not possessing either a distinguished colour, strong
lustre, or great -hardness, and losing its polish hj wearing; on
112 TREATISE ON GEMS.
account of its softness, it wears off at the edges. Very good speci*
mens of the Peridote from Brazil were brought into this country
from France, and commanded a good price a few years ago, viz :
from ten to fifteen dollars a carat.
XXVI. lOLITE.
This mineral has for a long time been brought from Spain, but
has lately been made more known and brought into notice by
Gordier, after whom it received the name Cordierite; it is called
likewise Sleinheilite, and has several other names, which I will
mention, in order that the reader may not be confused when the
same mineral is presented as a gem, under different names ; the
most appropriate name is Dichroite^ from its property of displaying
two colours when held in different directions ; it is also known as
Pelionie and Prismatic Quartz.
It occurs in regular six and twelve-sided prisms ; also, in crystal-
line grains, massive, and in pebbles ; its fracture is conchoidal and
uneven ; it is transparent, exhibiting an indigo-blue colour when
held in the direction of its axis, or viewed by transmitted light,
and appearing brownish-yellow when held at right angles; it pos-
sesses some double-refracting power. Sometimes a ray of light,
resembling that of the Star-sapphire, may be perceived in the Idite,
particularly when cut; it has a vitreous lustre; its colours are violet-
blue and indigo-blue, sometimes with a tinge of. black and bluish-
gray. It scratches glass, and is attacked by Topaz ; its streak-
powder is white ; it has a specific gravity of 2.88. By rubbing, it
becomes electric, and assumes polarity by heating ; it is difiicult to
fuse on the edges, and becomes then a grayish-green enamel: borax
fuses it into a diaphanous glass ; acids have no effect upon it ; it
consists of magnesia, alumina, and silica, with some oxide of iron
and water.
It is often found under the names of Lynx and Water-sapphire,
the first of a pale and the latter of a darkish-blue colour. It is found
in primitive rocks; also, in blue clay, in copper pyrites, in quartz
or felspar, and in small detached masses; the localities are Spain,
Sweden, Norway, Greenland, Siberia, Geylon, Brazil, Bavaria, and
the United States, (at Haddam, Connecticut.) If the stone is per-
fectly pure, it is used for rings and breast-pins ; 10 cut on a copper
wheel with emery, and polished on a tin [date with rotten-stone,
TREATISE ON OEMS. 113
and receives the form of a cabochon, in order to let it display its
proper colours, and in a cube form : its price is not very high ; the
jewellers value it as an inferior quality of the Sapphire, without
paying any regard to its phenomena of light. Good-sized speci-
mens are sold at about eight to ten dollars a piece ; at Paris, a good
lolite, ten lines long and eight and a half broad, was sold for one
hundred and sixty francs. When, a couple of years ago, the lolite
was discovered by Professor Mather, at Haddam, Connecticut, it
promised to be a valuable acquisition for American gems ; but the
supply was very scant, and its original locality appears to be ex-
hausted. Professor Torrey possesses a fine seal, in the form of a
c^be, from that locality, which displays its properties to the greatest
perfection.
A blue duartz is occasionally sold for lolite, but it may easily
be distinguished by its colours and hardness. Sapphire is con-
siderably harder than the lolite.
OPAL.
The precious variety of this mineral was known to the ancients,
and received its name on account of the play of colours which it has.
The Opal has a great many varieties, which are all considered
more or less gems, and find their application in jewellery ; they
will therefore be treated separately ; but, as general characters, it
may now be mentioned that Opal scratches glass but slightly,
while it is marked by rock-crystal ; it has a specific gravity of 2.06
to 2.11. It is infusible before the blow-pipe, but decrepitates and
falls into splinters ; it also dissolves with borax. Opal consists of
silica with water, some oxide of iron, and sometimes alumina.
XXVII. (A.) PRECIOUS OPAL.
This gem derives its name from the Greek word signifying the
eye, for the ancients believed that this stone had the power of
strengthening the eye. It was highly esteemed by them, as we
learn from Pliny, who thought that the play of colour originates
from the beautiful cdours of the Carbuncle, Amethyst, and Eme-
rald. He also states that the Roman Senator Nonius chose to
suffer banishment rather than part with a valuable splendid Opal
to Mark Antony. A similar beautiful large Opal was in modem
times excavated firom the ruins of Alexandria.
114 TREATISE ON GEMS.
The phenomenon of the play of colours in the Precious Opal
has not yet been satisfactorily explained. Haiiy attributei!) it to the
fissures of the interior being filled with films of air, agreeably with
the law of Newton's coloured rings, when two pieces of glass are
pressed together. Mohs contradicts this theory upon reasonable
grounds, which are, that the phenomenon would present merely a
kind of iridescence. Brewster concludes that it is owing to fissures
and cracks in the interior of the mass, not accidental, but of a uni-
form shape, and which reflect the tints of Newton's scale ; but it
is, in my opinion, sufficiently plausible, that the unequal division of
smaller and larger cavities, which are filled with water, produces
the prismatic colours, and for the simple reason that the Opal which
grows, after a while, dull and opaque, may be restored to its former
beauty if put for a short time in water or oil.
Although the Precious Opal was never found- in the East, yet it
bears the name of Oriental Opal among the jewellers: for in former
times the Opals were carried by the Grecian and Turkish mer-
chants from Hungary, their native locality, to the Indies, and were
brought back by the way of Holland to Europe as Oriental Opals.
The Precious Opal is found on small irregular gangues, nests of
the trachytic porphyry formation, and its conglomerates in Hun-
gary, particularly in the neighbourhood of the village of Czerwin-
ceza; also, in the Faroe islands. Saxony, and South America.
The Hungarian Opal is found of various qualities, and is obtained
firom mines which have been wrought for several centuries ; and,
according to the archives of that part of the country, there were, in
the year 1400, more than three hundred workmen engaged at the
mines near the above village ; whereas there are but thirty at pre-
sent engaged there, on account of the scarcity of large suitable
specimens.
The Precious Opal is principally used for rings, ear-rings, neck-
laces, and diadems; the smaller specimens for mounting snufiT-
boxes, rings, chains, &c. It is ground on a leaden wheel with
emery, and is polished with lOtten-stone and water on a wooden
wheel ; and, in order to increase its lustre, it is lastly rubbed with
putty, by means of buckskin, or a woollen rag and red chalk. Its
form is generally that of a semircircle, lens, or oval ; sometimes of
a table, and then also with some fsicets ; but great care has to be
taken that the edges, on account of the softness of the stone, do
TREATISE ON OEMS. 115
not wear off. It is also apt to spring in a temperature sudd^y
changing. When mounted, it receives a coloured foil, or a varie-
gated silk stuff, or a peacock-feather on the back, but it looks best
in a black casing.
Cracks and fissures may be removed by leaving the Precious
Opal for sometime in oil. Very frequently the Precious Opal is dis-
tributed in small particles in the matrix, called Mother of Opal,
which is cut by the jewellers as boxes, and other ornaments ; and
very often, too, this matrix is plunged ia oil, and is exposed to a
modemte heat, whereby the base grows blacker, and the true Pre-
cious Opal retains its ray of colours. In order to preserve the sur*
face of the Precious Opal against wear and tear, it is covered with
a thin plate of quartz crystal The Precious Opal still stands in
very high estimatioa, and is considered one of the most valuable
gems. The size and the beauty displayed by its colours determine
its value ; those playing in the red and green colours bear the
highest price. Its value has latterly increased on account of the
scarcity of the larger specimens. Formerly, a solitary large Pre-
cious Opal, playing in the red colour, was sold for two to three
hundred ducats ; and one pla3dng in both red and green colours,
about five lines long, was sold at Paris for two thousand four
hundred francs ; and lately a single Opal, of fine colours, and the
size of a dollar, was sold near the locality for three hundred thou-
sand florins ; in this country the Precious Opals are sold by the
importers at the rate of four to ten dollars per carat, and single spe-
cimens, suitable for pins or rings, from two to twenty dollars. The
mother of Opal is, however, much cheaper ; one of five lines size
is sold for three to five dollars.
All experiments for imitating the Precious Opal have hitherto
proved fruitless ; they were made either by preparing an enamel
and adding several metallic oxides, or by aflixing to the back of a
clear or common Opal or enamel, a pdished thin plate of the
mother of pearl, which may sometimes deceive the ignorant.
The imperial mineralogical cabinet at Vienna, contains the most
celebrated specimens of Precious Opal ; one, particularly, may be
mentioned here, which is the largest known ; it is four and three-
quarter inches long, two and a half inches thick, and weighs seven-
teen ounces. It was discovered about 1770, at the above locality, and
transported to Vienna. It displays the most magnificent cdours ;
116 TREATISE ON GEMS.
is perfectly pure, and not accompanied by any matrix. Half a
million of florins were offered for it by a jeweller of Amsterdam,
and refused on account of its uniqueness ; and the Y iennaians
have not yet dared to put even any approximative value upon it.
XXVni. (B.) FIRE OPAL.
This mineral was first brought into notice by Baron Humboldt,
who found it in Mexico.
It occurs massive ; has a conchoidal fracture ; is transparent ;
of strong vitreous lustre ; colour hyacinth red, running into honey,
wine-yellow, showing carmine-red and greenish reflections ; some-
times containing dendritic drawings. Its specific gravity is 2.02 ;
loses one and a half per cent, by calcination, and leaves pale flesh-
red fragments. It is found in the trachytic porphyry, in Mexico,
and in the amygdaloid of the Faroe islands.
Since the Fire Opal is very little known, it has not yet been
employed in jewellery, but bids fair to find a[^lications. It is
ground on a leaden wheel with emery, and polished with rotten-
stone on a wooden wheel. The forms of cabochon, table, or
pavilion, might suit very well as ring-stones.
The cabinet of the University of Bonn possesses a very large
and fine Fire Opal, of the size of the fist. The largest specimen I
have seen is in the royal mineralogical cabinet at Berlin, which was
deposited by Baron de Humboldt on his return from South America,
and which, if I recollect it well enough from the year 1827, must
be at least six inches long and four inches thick. This is the
largest specimen he ever found. A collection of six shades of Fire
Opal, with six more varieties of the other Opals, was presented to
me in the year 1828, when in Berlin, by the Counsellor Bergeman,
who received at that time a considerable quantity of polished
specimens from the Faroe islands, but all of small size. A splen-
did collection of fire Opals was brought from Guatemala some
years ago to this country.
•
XXIX. (C.) COMMON OPAL.
This mineral occurs massive and in rolled pieces; also as
stalactites ; has a conchoidal fracture ; is translucent and semi-
transparent ; has a strong vitreous and resinous lustre ; its colours
are milky, yellow, reddish, greenish-white, honey-yellow, wine-
TREATISE ON GEMS. 117
yellow, flesh, brick-red, and olive-green ; sometimes dendritic, (Moss
Opal.) Its specific gravity is 1.9 to 2.1.
The Wax and Pitch Opal are subordinate to this variety. It is
found in the same rocks as the Precious Opal, in Hungary ; in the
hematite rocks of Saxony ; in the Serpentine of Silesia ; in cavities,
of trapp and the amygdaloid rocks of Iceland ; Faroe islands ;
and in the United States, (Pennsylvania and Connecticut.)
It is used for rings, pins, and cane-heads ; but is, on the whole,
Hot a favourite among the jewellers, and has no great value,
because it is soft and brittle ; the paste, which may be made from
white enamel, is sometimes much prettier than the real stone.
XXX. (D.) HYDROPHANE.
The name of this variety of Opal has reference to its peculiar
property of becoming transparent, and opalescent after immersion
in water. The ancients called this stone Lapis Mutabilis, and
Achates Oculus Mundi. It is a common or Precious Opal, of porous
texture ; adheres strongly to the tongue ; is translucent, and absorbs
water with avidity, giving off at the same time air-bubbles ; it thus
assumes a high degree of transparency, and sometimes the property
of displaying the finest prismatic colours, equal to the Precious
Opal. This phenomenon tends strongly to explain the display of
the prismatic colours of the Precious Opal ; the more so as the
Hydrophane loses this property on getting dry.
It has, when dry, a white, yellowish, or reddish colour, and a
specific gravity of 1.95 to 2.01 ; and according to Haiiy, a Hydro-
phane, having been immersed for four minutes in water, gained
thirty-four centigrammes.
The Hydrophane is found in the porphyry of Hungary, France,
Iceland and the Faroe islands. Large pieces of good and fine
specimens of Hydrophane are wrought and used in the same
manner as the Precious Opal.
It is said that the Hydrophane becomes much quicker transpa-
rent in warm than in cold water ; the quickest in spirits of wine ;
after which, it loses this property the sooner ; but when boiled
in oil, it retains it, to a certain extent, for years.
If the Hydrophane is well dried and soaked in melted white
wax, or spermaceti, it assumes the property, when warmed, of
becoming translucent, and of displaying browish-yellow or gray
colotirtt; it IS then called Pyroph^ine.
118 TREATISE ON GEMS.
The Hydrophane was once coloured violet or red, by means of
a decoction of logwood and alum.
The price of the Hydrophane is very high, on account of its
great scarcity, and because it is very seldom found in large lumps.
XXXI. (E.) SEMI-OPAL.
This variety of Opal was formerly considered to be a pitch-stone,
and if it assumes the form of petrified wood, it is called Wood Opal.
It has a conchoidal and even fracture ; it is translucent and opaque ,'
of a resinous and vitreous lustre ; its colours are yellowish, gray-
ish, and brownish, the colours running mostly into one another ;
sometimes the colours divide themselves riband-like. The Wood
Opal is mostly brownish, and displays, more or less, a ligneous
aspect, with the forms of asts, or branches.
The Semi-Opal is found on gangues, in the trachytic porphyry
in Hungary, in the Serpentine in Silesia, in the amygdaloid on
Iceland and the Faroe islands; likewise in Moravia, Saxony,
France, Greenland ; and in the United States, (Maryland and
Pennsylvania.)
The Semi-Opal, on account of its taking a high polish, is used
for many purposes in jewellery. There is an establishment for
manufacluring snuff-boxes from Wood Opal, in Vienna, and lately
the varieties of Wood Opal, with layers of Chalcedony, or Semi-
Opal, have found a useful application for the cutting of cameos.
The Semi-Opal is ground and polished like the Precious Opal, but
with more difficulty, on account of its being more brittle. The
form which it easily receives is en cabochon, but without &cet8.
The price of the Semi or Wood Opal is low.
XXXII. (F.) CACHELONG.
According to Blumenbach, the name of this mineral is of Mon-
golian derivation, meaning "a pretty stone;" and according to
Phillipps it bears its name after the river Cach, in Bucharia, on
whose shores it occurs frequently in loose conglomerates. This
mineral was hitherto arranged under the head of Chalcedony, but
properly belongs to Opal.
It occurs massive, as a covering of other minerals, rarely reni-
form, often traversed with fissures in different directions. It has a
conchoidal fracture ; is opaque, and of a pearly lustre ; milky-
TREATISE ON GEMS. 1 19
white, turning sometimes to a yellow or a red colour ; and exhibits
dendritic figures of manganese or green earth. It scratches white
glass ; has a specific gravity of 2.2 ; it decrepitates when first
brought before the blow-pipe, but yet undergoes no change;
dissolves with borax, slowly, at a white heat.
It is found in the same manner as the Chalcedony, sometimes
encrusting or penetrating it ; in the amygdaloid of Iceland, Green-
land, the Faroe islands, the Hematite of Corinthia, the United
States, (Massachusetts,) and Nova Scotia; in Bucharia, in the
sand of the river Cach, it is found loose.
Cachelong is much used in jewellery for rings, seals, <fec. The
Calmucks of Bucharia manufacture of it tools and other domes-
tic articles. It is cut on a copper wheel with emery, en cabochon,
and receives the polish on lead plates, by means of rotten-stone
and putty. The price of the Cachelong is pretty considerable, on
account of its beauty and scarcity ; as the specimens most frequently
found in the above localities are seldom in layers of more than one-
quarter of a line, alternating with Chalcedony.
XXXIII. (G.) JASPER OPAL.
This mineral stands between Jasper and Opal ; and, although
considered by Werner as belonging to the first, ought, nevertheless,
more properly to be arranged with the Opal, on account of its con-
taining water in its composition.
The Jasper Opal occurs massive, in specks, stalactiform, and in
geodic masses ; it has a conchoidal fracture ; is translucent on the
edges, or opaque ; is of a strong resinous lustre ; its colours are
gra-y, yellow, red, and brown. Its specific gravity is 2.0 to 2.1. It
consists of silica, water, and oxide of iron, amounting to forty-
seven per cent. It is found in the trachytic breccias of Hungary ;
also, in Saxony and Siberia. The best light and pure specimens
are used for dagger and sword handles in Turkey. The price of
Jasper Opal is low.
XXXIV. OBSIDIAN.
This mineral was very familiarly known to the ancients, and its
name is said to be derived from a Roman, who first brought it to
Rome from Ethiopia. Pliny states that the Romans manufactured
mirrors and gems firom it ; and the Mexicans and Peruvians manu-
120 TREATISE ON GEMS.
factured their knives, razors, and sword-blades from the Obsidian,
which appears to have served as a complete substitute for other
materiab with those nations, who were yet unacquainted with the
use of gems for weapons and utensils of various kinds. The Baron
Humboldt says that Cortez mentioned, in his letter to the Emperor
Charles Y., having seen razors of Obsidian at Tenochittan ; and
the above naturalist likewise discovered himself, on the Serro de las
Nabajaz, in New Spain, the old shaft that was used for raising the
rough Obsidian, with relics of the tools and half-finished utensils.
The inhabitants of duito manufactured magnificent mirrors
from Obsidian, and those of the Azores and Ascension islands,
and Guiana used splinters of the Obsidian as points for their
lances, razors, &c.
Specimens of arrows and other articles, such as octangular
wedges, were presented a few years ago to the New- York Lyceum
of Natural History, being relics from the ruins of Palenque. In the
collection of Columbia College are some razors, or sacrificial knivee,
the gift of the Hon. J. R. Poinsett.
Obsidian occurs massive, in roundish or obtuse lumps, balls, and
grains ; has a conchoidal fracture ; is semi-transparent and trans-
lucent on the edges ; it has a strong vitreous, and sometimes even
metallic lustre ; its colours are either pure black, grayish, brownish,
greenish-black, yellow, blue, or white, but seldom red ; it sometimes
displays a peculiar greenish-yellow shine, when it is called the
iridescent Obsidian ; there is rarely more than one colour in the
same specimen with stripes and specks. Obsidian scratches^white
glass indifferently, but is scratched by Topaz ; its streak-powder is
white: it has a specific gravity of 2.34 to 2.39. Obsidian is
sometimes magnetic, so that small pieces show their magnetic
poles. Before tbe blow-pipe, the black variety is fiisible with much
difficulty ; and even at a white heat it does not mdt into a solid
glass ; but the gray and brown variety (Marekanite) jswells readily
into a spongy mass.
Obsidian consists of silex, alumina, with a little potassa, soda,
and oxide of iron.
The names, Iceland Agate, lava, black-glass lava, volcanic
lava, are all synonymous, and the mineral called Bottlestone, in
round grains of the size of a pea, is nothing but a green Obsidian.
The Obsidian, sometimes, forms the cement of whole moun-
TREATISE ON OEM& 121
tain chains^ often deposites in the trachyte and the streams
at the foot of some volcano ; also, among the volcanic ej^tions,
and occurs in loose lumps in the sand of rivers, and at thi^looi of
mountains. It is found in Iceland, Teneriffe, the Lipari islands,
Peru, Mexico, Sicily, Hungary, Asiatic Russia, the Ascension
islands, and on all the volcanos of former and present times.
In the New- York Lyceum of Natural History are several
interesting specimens, presented by Don Correa, of Tobasco, from
the mins of the city of Palenque ; such as concave or triangular
wedges, and other masses of Obsidian from various localities.
It is employed for several useful and ornamental purposes ; such
as the making of ear-rings, necklaces, brooches, snuff-boxes, knife-
handles, (fcc. It is particularly worn as mourning jewellery ; it
requires, however, much care in working, being extremely brittle.
It is ground on lead wheels with emery, and polished with rotten-
stoiui. It is kept in favour by the jewellers on account of its high
pdisb; but its value is very indifferent, excepting that of the
iridescent Obsidian, which commands a high price, and is some-
times seen cut en cabochon, and set in rings.
There is no doubt but what Obsidian is of volcanic origin,
being mostly found in the neighbourhood of volcanos, and that it
is a glass, produced by the volcanic fire, as it is a combination of
silex and alkaline substances. The Neptunic theorists have
endeavoured to prove that it is occasionally found with the remains
of decomposed granite, gneiss, and porphyry, with which it even
alternates in layers.
XXXV. AXINITE.
The name of this mineral is derived from a Greek word, signi-
fying an axe, and was applied to it on account of the resemblance
of its cryptabtoibat implement; it is also called by some English
mineralogiM.Thumer-stone, from its first locality. The Axinite
occurs in a variety of crystalline forms, to be reduced to the rhombic
forms, viz : an oblique rhomb, or four-sided prism, so compressed
that the edges appear sharp, like the edge of an axe ; likewise,
massive and in specks ; its fracture is uneven ; it is translucent on
the edges, or transparent; has a simple refraction of lights its
lustre is vitreous ; also, resinous ; its colours ^e violet-blue, brown,
gray, and yellow ; it scratches white gtass, but is scratched by
a
122 TREATISE ON GEMS.
Topaz; has a white streak-powder; its specific gravity is 3.27;
it becomes electric by rubbing or heating ; before the blow-pipe it
fuses into a grayish-brown glass ; acids have no effect upon it ; it
consists of lime, alumina and silex, with oxide of iron and man-
ganese. It occurs on gangues and layers of various formations,
principally the primitive ; and is found in Daupbine, Pyrenees,
Gothard, Saxony, (Thum,) Norway, &c.
This mineral takes a very high polish, particularly those speci-
mens from Daupbine, but has hitherto, on account of its scarcity,
not found much application in jewellery, but will hereafter be a
great acquisition, as it may be used for rings, pins, and other small
ornaments.
FELSPAR.
The varieties of this mineral are mostly crystallized, and in very
numerous forms ; but they are all distinguished by two great
characters, which are, the foliated structure and peculiar lustre ;
the principal form is an oblique prism with unequal sides. Felspar
scratdies glass and is scratched by rock-crystal; its streak-powder is
white ; ^t has a specific gravity of 2.5 to 2.6 ; before the blow-pipe
it fuses wi\h difficulty ; on charcoal it becomes vitreous and white ;
fuses with difficulty on the edges to a translucent white enamel ;
the acids have no effect upon it ; it consists of potash, alumina,
and silex.
XXXYI. (A.) ADULARIA.
This mineral occurs in crystals, crystalline fragments, and solid
masses ; its fracture is uneven ; it is translucent on the edges ; has
double refraction of light ; the lustre is vitreous and pearly, more
especially when cut and polished ; it throws oui greenish and bluish-
white chatoyant reflections from the interior; it cleaveB in two direc-
tions ; the crystals often present the hemitrope Ibrm, which in polished
specimens becomes obvious from the d^erent directions of the
laminee ; its colours are limpid-white, greenish, grayish, and blu-
ish, frequently with a peculiar pearly shine, and sometimes it is
iridescent.
In commerce, the Adularia goes under various names, such as
Moon-stone, Sun-stone, Girasol, Fish-eye, Ceylon or Water OpaL
In the Moon-stone the colour is white, with small bluish or green-
TREATISE ON GEMS 123
ish shades, but the base is semi-transparent and milky ; whereas
the Sun-stone shows a yellow and reddish play of colours. The
Adularia is found in gangues and cavities of the granite and gneiss,
and limestone, and in pebbles from Ceylon, Greenland, Bavaria,
St Gothard, Tyrol, Dauphine, and in the United States, parti-
cularly at Ticonderoga, (New- York,) near Liake Champlain, Mary-
land, Pennsylvania, Connecticut, and Massachusetts. The Adu-
laria from St Gothard is found in very large masses ; I saw, in
1827, in the cabinet at Zurich, in Switzerland, groups of crystal-
lized Adularia, measuring two feet in length and one foot in thick-
ness, the splendor of which dazzled my eyes.
Adularia, displaying a good colour, and strong pearly reflections,
is now much used in jewellery, for rings, pins, and other smaller
ornaments. Generally specimens which possess these qualities are
cut out of large lumps, then ground on a lead wheel, en cabo-
chon form, and polished with rotten-stone ; they are, in general,
mounted in a black case, whence it best shows its reflections.
The Moon-stone commands a good price; exquisitely fine speci-
mens, of the size of a bean, are worth from five to ten dollars,
and some of them were sold at Paris, of six lines diameter, for
seven hundred and five francs, and four lines for two hundred
and three francs.
The largest Moon-stone, in a brooch, three-fourths of an inch in
length, I have seen in the possession of Francis Alger, Esq., of
Boston ; and rough specimens, with most splendid reflections, I
have admired in the collection of Dr. M. Gay, of the same city.
Both these gentlemen are fortunate in possessing uniques in this
country, which are of no ordinary scientific and commercial value.
XXXVIL (B.) COMMON FELSPAR.
This Felspar occurs in crystals, massive, and disseminated ; its
fracture is uneven and splintery; is translucent; has a pearly and
vitreous lustre ; its colours are white, gray, red, yellow, and green,
in their various shades, sometimes with « variegated bluish, green-
ish, or reddish play of colours : its texture is compact, or minutely
foliated.
The Amazon Stone, or green Felspar, is from Siberia ; likewise
splendid grass-green Felspar was found in the United States, at
Southbrid^ and Hingham, Massachusetts, and Cow-Bay, New-
124 TREATISE ON GEMS.
Vork ; of apple-green colour at Topsham, Maryland, and near
Baltimore. Also, the American glassy or vitreous Felspar, found
in Delaware, which ought properly to be quoted as a distinct spe-
cies,, is arranged with this variety.
Felspar is widely diffused all over the globe, and with a few
exceptions is more common than any other mineral ; it forms a
constituent part of most primitive rocks, such as gneiss, granite,
d^c. ; is the principal ingredient of the Syenites, Porphyry, and, in
fact, with a small per centage of other minerals, forms whole
mountain ranges and chains in various parts of the globe : such
r we see in Siberia, the north and west of Scotland, &c., all of which
are surrounded by Felspar. Immense beds exist in the United
States : around Wilmington, in the State of Delaware, is an inex-
haustible deposite of exquisite and perfectly pure Felspar ; and in
Connecticut and on the North River we see beds of the foliated
Felspar extending for miles. Sweden, Norway, and Greenland
are likewise great depositories for the common Felspar.
The Amazon-stone is used in jewellery for ringSi pins, seals|
snuff-boxes, &c. It is principally cut at Katherineburgh| Siberia,
where it is ground on a leaden wheel with emery, and' polished
with rotten-stone on a wooden wheel ; its form b that of en cabo-
chon, and sometimes the mixed and pavilion-cut, when the table
is to be cut pretty large, and arched, in order to display more dis-
tinctly its peculiar colours.
Common Felspar is of no great value, and only the AmaoM^-
stone is used in jewellery, which commands a good price. Cut
specimens, suitable for ear-rings or brooches, are worth from three
to five dollars.
A very fine specimen of the Amazon-stone, in its rough state,
may be seen in the New- York Lyceum of Natural History. The
imperial cabinet of St. Petersburgh possesses two vases of this stone,
which are nine inches high and five and one half inches in diame-
ter. Although our vitreous Felspar has not yet been brought into
use f<Hr the purposes of jewellery and other ornaments, yet it bids
fair to contribute, at one day, much to the national wealth of this
country, for it is the best material for porcelain, china, and earthen-
ware. Already have many cargoes of this beautiful mineral been
shipped to France and England, (six hundred tons of the Connec-
ticut, Middletown, Felspar were, according to Professor Sbephard,
TREATISE ON GEMS. 126
last year shipped to Liverpool, and one hundred tons to the Jersey
porcelain manufactory,) where the manu&cturer appears to appre-
ciate better the purity of ingredients for the purposes just mentioned.
Instead of receiving, as hithertd, the manufactured goods from
abroad, made €i our own raw material, it is earnestly to be hoped
that we shortly will acquire skill and exert sufficient industry to
compete with foreign manufacturers in the art of making porcelain,
with the superior material which Nature has so abundantly lavished
on this continent I possess a splendid slab of the vitreous Fel-
spar, of one square foot, free from any admixture, and imposing
in appearance.
XXXVm. LABRADOR.
This mineral was heretofore considered as a variety of Felspar ;
but it has latterly been separated from it, and ought, therefore^ no
more to be called Labrador Felspar, the name by which it is
known in all mineralogical works.
The Labrador was first discovered by the Moravian missioila-
ries on the island of St. Paul, on the coast of Labrador ; and
according to others, by Bishop Launitz, in 1775, when it was
brought to Eun^. The Labrador occurs in crystalline masses,
massive, and in boulders ; it is of an uneven and conchoidal
fracture ; its lustre is vitreous, and in one direction pearly ; it is
translucent ; its colours are gray, with its various shades, such' as
bliiekisb or whitish-gray, with spots of an opalescent or iridescent
vivid play of colours, consisting of blue, red, green, brown, yellow,
or orange, according to the direction in which light is falling upon
the specimen ; sometimes several of these colours are perceptible at
the same instant, bnt more commonly they appear in succession as
the mineral is turned towards the light. These colours are said to
originate in fissures which intersect the texture of the mineral, as
they are only perceptible from that side where they fall together
with the foliated structure, and not like the Opal, whose mads is
supplied with fissures running in all directions.
The Labrador scratches white glass, is scratched by rock-crystal,
and is somewhat less hard than Felspar ; its specific gravity is 2.71
to 2.75 ; before the blow-pipe it fuses with difficulty, and is said to
lose its play of colours ; it consists of silex, alumina, lime, soda^
with some oxide of iron and water. The Labrador is found as a
126 TREATISE ON GEMS*
rock and boulder, in St. Petersburgh, Norway, Bohemia, Saxony,
Sweden, St. Paul's Island on the coast of Labrador, and in the
United States, in Essex county, (New-Jersey,) at the mouth of the
North River, near Lake Champlain, New-York, where, according
to the description given me by Archibald Mclntyre, Esq., its
splendid colours are seen on both sides of the water, but a few
yards apart, and the effect of the rays of the morning sun falling
upon the rock and water at the same time, is said to equal that of
the prismatic spectrum thrown into a dark room.
The Labrador is used for rings, pins, buttons, snuff-boxes, letter-
holders, cane-heads, and other ornaments, such as vases and larger
articles ; but care has to be taken in grinding, that the direction
where the play of colours is visible is kept straight, and that it is
cut en cabochon. The price of the Labrador is not very high,
but soon after its discovery, a Doctor Anderson, having described
the mineral as displaying all the variegated tints of colour that
are to be seen in the plumage of the peacook, pigeon, or most
delicate humming-bird, and specimens having been carried to
England, so great was the avidity to possess it, that small pieces
were sold for twenty pounds sterling. The present price of good
specimens is from two to ten dollars; and a few yearp ago I
purchased some letter-holders, which are beautiful specimens, for
which I paid four dollars a-piece. The largest specimens of
Labrador are in the collections of the Mineralogical Society, and
in the museum of the Academy of Sciences at St Petershuigh,
which were found on the shore of the Pulkouka ; one of them
weighs ten thousand pounds. I have in my possession a rough
specimen of the Labrador of this State, merely rubbed off on the
surface, and its colours, I venture to say, equal, if they do not
indeed excel, in every respect, those of the specimens jfrom St.
Paul's Island ; and I anticipate the day when the citizens of New-
York will take as much pride in possessing Labarador table and
mantel-slabs, as they now do in employing the Italian and Irish
marble for these purposes ; for the resources appear to be inexhaust-
ible in the rocky county of Essex. We do not see many speci-
mens brought from the coast of Labrador, and I was informed by
Mr. Audubon, on his return from that quarter, that he could not
find any specimens. Mr. Henderson, of Jersey City, who presented
me the above-mentioned rough specimen of Labrador, had likewise
TREATISE ON GEMS. 127
splendid small polished specimens in breast-pins, displaying all the
properties in their fiill beauty. The same gentleman, who travelled
last summer in company with several scientific State geologists,
mentions that they picked up beautiful specimens at the height of
five thousand seven hundred feet above the level of the sea.
In the collection of Columbia College is a fine specimen of
Labrador, brought from Gaspy, Lower Canada, by the Hon. Mrs.
PercivaL
XXXIX. HYPERSTHENE.
This mineral was formerly annexed to Hornblende, but has
latterly been separated ; its name is derived from the Greek, and
means of superior strength, in reference to the great hardness and
specific gravity which it possesses.
The Hypersthene is found in crystalline masses; it has an
uneven fracture ; it is opaque, and its colours are dark-brown, red,
greenish or grayish-black ; the cleavage is parallel to the sides,
and shorter diagonals of a rhombic prism ; its lustre is metallic,
and when viewed in one certain direction, copper-red, light-brown,
or gold-yellow, and in others it has a greenish play of colours. It
scratches glass, has a darkish-green streak-powder, and has a
specific gravity of 3.38 ; it is easily fusible before the blow-pipe
on charcoal into a grayish-dark bead; acids have no effect
upon it ; it consists of magnesia, silex, alumina, and lime, with
some water.
It is found forming a constituent of the Labrador rock, on the
coast of Labrador, Greenland, and in the Uniled States, oa
Brandywine Creek in Pennsylvania, and in Essex county, New-
Jersey ; fine specimens have been found in Hingham, Massachu-
setts. The French jewellers have lately begun to introduce this
mineral for rings, pins, and other ornaments, on account of its
high polish and beautiful colour. The best coloured pieces are
cut out of the mass, and ground on a lead wheel with emery en
cabochon, and polished with rotten-stone. Beauty of colour and
other qualifications determine the price of this stone ; at Paris a
Hypei'sthene, en cabochon cut, eight to ten lines long and six lines
broad, was sold for one hundred and twenty francs.
The mineral is, however, pretty rare, and has not yet been
fiilly introduced.
130 TREATISE 01^ GEMS.
ground with emery on a lead wheel, and polished with rottennstone
on a tin wheel. The rocks which yield the Lapis Lazuli, where
it is contained in specks, are likewise cut for ornamental purposes,
such as snuff-boxes, vases, candlesticks, cups, columns, can&>
heads, &c. ; also, for architectural ornaments and stone mosaic ;
the larger specimens, having the specks regularly disseminated on
a white ground of the rock, are those selected for cutting. The
most important use of this mineral is that of furnishing the cek-
brated and beautiful pigment called Ultramarine-blue, used by
painters in <h1, and said never to fade. The Lapis Lazuli takes a,
very high polish, but becomes dull again after being used for some
time. It is sometimes imitated with the Lazulite or Azure-stone,
the blue carbonate of copper, which, however, is not near so hard
and effei'vesces on testing with nitric acid. Those specimens
having the iron pyrites enclosed aie difficult to polish well, on
account of the unequal hardness of the two minerals.
The value of the Lapis Lazuli, although depending upon its
purity, intensity of colour, and size, has nevertheless much dimin-
ished when compared with its former prices.
The Chinese, who have for a long time employed the Lapis
LazuU in their porcelain painting, call the pure and sky-blue stone
Zuisang, and the dark-blue, with disseminated iron pyrites, the
Tchingtchang, preferring the latter to the former ; they work the
same for many ornainents, such as vases, snuff-boxes, buttons and
cups.
In the palace which Catharine II. built for her &vourite Orlof^
at St. Petersburgb, there are some apartments entirely lined with
Lapis Lazuli, which forms a most magnificent decoration. I have
several slabs, three inches long, and of fine azure-blue cdour, in
my possession. ;
The production of Ultramarine has been known since 1502,
and was already employed, under the name of Azurum Ultrama-
rinuro, by CamiUus Leonarus.
The process of preparing the Ultramarine was known as early
as the fifteenth century. The colour is now mostly prepared at
Rome, in the following manner : those pieces which are free from
pjrrites specks, are first calcined and pulverized; the powder is
then formed into ^ mass with a resinous cement, (pastello,) and
iiised at a strong beat; this is then worked with the hands in
TREATISE ON GEMS. 131
0oft water, whereby the finest colouriii^ particles are disengaged
in the water, which will soon be impr^nated with the blue colour;
a fresh portion of water is then taken, and the same operation is
continued until the remains are odourless. The Ultramarine, after
a short time, settles to the bottom of the vessels, and is carefully
separated and dried. If the Lapos Lazuli was of the best quality,
the product will be from two to three per cent. That colour
which remains yet in the. mass is of an inferior quality, and
is called the Ultr&tmarine ashes ; it is of a paler and more red-
dish colour.
Good Ultramarine has a silky touch, and its specific gravity is
2.36. It does not lose its colour if exposed to heat, but is soon
discoloured by acids, and forms a jelly. In order to distinguish
the pure Ultramarine from numerous spurious and adulterating
colouring materials, such as indigo, Prussian-blue, mineral-Uue,
&c., it is only necessary to test the article in question with some
acid, when after a few minntes the real Ultramarine is discoloured,
yielding a clear solution and a white residuum. The real Ultra-
marine has always been at a very high price, on account of the
small product obtained from the material. An ounce of the purest
Ultramarine is sold in France for two hundred to two hundred and
fifty francs, which is not within the reach oi all painterg.
In the year 1828, the discovery was made by Professor Gmelin,
in Tubingen, that sulphuret of soda was the proper material for
imitating this precious and valuable pigment. By his experiments
he succeeded in preparing this substance from silex, alumina, soda,
and sulphur, producing a ccAoar in every respect corresponding with
the true cfAour of the Lapis Lazuli, and bearing the same relation
to acids as the genuine Ultramarine. Thisj for economy, has
become a great object to painters and cokmr-men, since a whole
pound of it may be purchased in France for twenty francs. As it
bids frbir to meet with a great consumption, being even substituted
for cobak in Umog paper, thread, and other stufls, several manu-
frbcturers have already been induced to engage liai^ly in its pre-
paration ; and there is now a very extensive establishment in full
operation by M. Cruimet, tbt^e' leagues from Lyons, who likewise
claiitns the priority of its discovery : the royal porcelain manufactory
at Meisseiij in Saxony, also prepares it. The process for rtiaking*
the artificial Ultramarine, a& it was first described by Gmdin, is^
13B TREATISE ON OEMS.
here given, as it was published in the AnntUea de Chimin The
whole process is divided into three parts : —
1. The pure hydrate of silica is prepared by fusing fine pulver-
ized quartz or pure sand with four times its own weight of salt of
tartar, dissolving the fused mass in water and precipitating by mu-
riatic acid ; also, the hydrate of alumina is prepared from alum in
solution, precipitated by ammonia.
2. Dissolve the silex so obtained in a hot solution of caustic soda,
and add to seventy parts of the pure silex seventy-two parts of alumi-
na ; then evaporate these substances until a moist powder remains.
3. In a covered Hessian crucible, a mixture of dried sal soda,
one part to two parts of sulphur, is heated gradually, until k is fully
fused, and to the fused mass add small quantities of the earthy
precipitate, taking care not to throw in fresh quantities imtil all the
vapours have ceased ; after standing for an hour in the fire, remove
the cruciUe, and allow it to cool. It now contains the Ultramarine,
mixed with an excess of sulphuret, which is to be removed by levi-
gation ; and, if the sulphuret is still in excess, it is to be expelled
by moderate heat. Should the colour not be uniform, levigation
is the only remedy.
XLm. KYANITE.
The name of this mineral is derived firom the Greek, signifymg-
blue, and was given to it on account of its blue cokair. It has
been known for many centuries, having been cut by a German
lapidary, Cornellius, in the reign of James lY., under the name of
Sappare, by which it is yet known among the French jewellers.
It occurs in masses composed of a confused aggregation of crys-
tals, and in distinct crystals of four or eight-sided prisms, much
compressed, with two broad shining faces. The crystals are gene-
rally closely aggregated, and are crossiilg or standing on each other
in a hemitropic form, so as to present a singular and curious aspect.
Some of the crystals are curved, others are corrugated or wrinkled,
as though they had been pressed endwise, or had not room to
stretch themselves at full length ; others are pressed into triangular
shapes, 6oc. It has a foliated structure ; uneven fracture ; is trans-
parent and translucent; possesses simple refraction of light; its
lustre is vitreous and pearly; its coburs are azure-blue, passing
into light blue or bluish-white and bluish-green* It scratches white
TREATISE ON GEMS. 133
glasBi and is attacked by Topaz or a good file ; yields a white
streak-powder ; has a specific gravity of 3.63 to 3.67. It becomes
electric by rubbing, and often exhibits positive and negative electri-
city in one and the same specimen ; it is infusible before the blow-
pipe, but, with borax, fuses with difficulty into a transparent limpid
glass : acids have no efiect upon it.
It consists of alumina and silex, sometimes combined with oxide
of iron and water.
The Kyanite is found in micaceous, talcose, and argillaceous
slate, at St. Gothard, and on the Tyrol, in Switzerland ; in Styria,
Corinthia, Bohemia, Spain, and Siberia ; also, in the United States,
of the purest azure-blue colour : large specimens in Litchfield, Had-
dam, and near New-Haven, (Connecticut;) Chesterfield, Conway,
Granville, Deerfield, and Plainfield, (Massachusetts;) Grafton, Nor-
wich, and Bellows Falls, (Vermont ;) Oxford, (New-Hampshire ;)
East Bradford, East Marlborough, and Chester county, (Pennsyl-
vania;) likewise, of a delicate light-blue, variously shaded, in
Foster, (Rhode Island.)
The Kyanite has not yet been received as a favourite among the
jewellers, (perhaps from not being generally known by them,) or
dse it would long since have been cut for various ornamental pur-
poaies, more particularly in this country, where the localities are so
numerous and the colour so beautiful. When well cut, it may be
substituted for the Sapphire. I indulge the hope that some jewel-
lers or lapidaries may take a hint from this remark. In France
and Spain, it has for some years past been used for rings, brooches,
and other jewellery. It is generally ground with emery on a lead
wheel, and with pumice-stone polished on a wood plate, receiving
the last polish with rotten-stone. The form it receives is en cabo-
chon or table-cut Usually, the best parts of good uniform coloured
speciiuens are picked out for cutting.
The price of this stone depends upon the hardness, colour, and
polish : perfect specimens command a good price. Very fine cut
specimens were brought from the East Indies, and sold in France
as Sapphires.
XLIV. TURQUOISE.
The name of this mineral is probably derived from the country
whence it was .generally brought into market, which is Turkey.
134 TREATISE ON GEMS.
In ancient times it was used as a remedy for several diseases, and
was also worn as an amulet against disasters. It occurs in reni-
form masses and in specks ; has a conchoidal fracture ; is opaque ;
of a dull and waxy lustre ; its colours are blue and green, from
sky-blue to apple-green, sometimes yellowish ; it scratches Apatite,
but not duartz nor white glass, and is easily attacked by the fde ;
it has a white streak-powder ; its specific gravity is 2.86 to 3.0 ; it
is infusible before the blow-pipe alone, but loses its blue colour and
becomes yellowish-brown ; but it fuses with borax into a limpid
glass. Muriatic acid has no effect upon it. It consists of alumina,
phosphoric acid, water, oxide of copper, and protoxide of iron.
There are two kinds of Turquoise used in trade, which differ
materially in their composition, and are from different localities : —
1. The Turquoise from the old rock, or the true Turquoise,
which is generally called the Oriental Turqimse, that we receive
fi-om Persia, and is of a sky-blue and greenish colour.
2. The Turquoise from the new rock, the Occidental or bcwie
and tooth Turquoise, which is either dark-blue, light-Uue, or
bluish-green ; the surface of this mineral is sometimes traversed
by veins which are lighter than the ground ; it is of organic origin,
consisting, probably of coloured teeth of antediluvian animals;
it owes its colour, according to Bouillon Lagrange, to two per cent
of phosphate of iron, which is contained in it. It is easily distin-
guished from the Oriental Turquoise by its structure, internally
foliated and striated, which is an indication of a bony compo-
sition ; it does not take so high a polish, gets discoloured in distilled
water, dissolves in acids, and is totally destroyed by aquafortis. Its
localities are Siberia, Languedoc in France, and other places.
The true or Oriental Turquoise is found on small gangues of
bog-ore and siliceous shiste, in boulders, &c. A mineral by the
name of Kalaite, occurring as a coating to siliceous sinter, of Sile-
sia and Saxony, was some years ago discovered. The Turquoise
is brought to market by the merchants of Bucharia, ready cut and
polished ; and in Moscow it is wrought over, being ground on a
lead wheel with emery, and polished with rotten-stone or pumice*
stone on a tin wheel ; and its last and best polish is received from
the jewellers, by rubbing with a Hnen rag and rouge. Since it is
often traversed with fissures and cracks in the interior, it requires
great caution in grinding. It is mostly cut in ttie form m tabo-
TREATISE ON GEMS. 135
chon ; ako, as thick or tablenstones, and is used for numerous pur-
poses in jewellery, such as rings, ear-rings, brooches, and also for
mounting around the most precious gems.
The price of the Turquoise has, for the last ten years, much
decreased ; that of an Oriental is generally four times higher than
the occidental : one, the size of a pea, is worth about ^ve dollars ;
a good Turquoise, sky-blue and oval-cut, five lines long and four
and a half lines broad, was sold in France for two hundred and
forty-oEie francs ; and a light-blue, greenish lustre, and oval cut,
five and a half lines long and five broad, was sold for five hundred
francs ; whereas an occidental Turquoise, four lines long and three
and a half broad, brought only one hundred and twenty-one francs.
The Turquoise is very well imitated artificially, so much so as to
render it difficult to discover the difference between that and the
real, by adding to a precipitated solution of copper and spirits of
hartshorn, finely-powdered and calcined ivory-black, and leaving
the precipitate to itself for about a week, at a moderate heat, and
afterwards carefully drying the same, and exposing to a gentle
heat This artificial Turquoise is softer than the real, and cuts
with a knife in shavings, whereas the genuine 3nelds a white
powder. The real Turquoise displays in the day-time a sky-blue,
and at night-time a light and greenish colour ; is not attacked by
acids, and resists the fire.
In the museum of the Imperial Academy at Moscow is a Tur-
quoise more than three inches in length and one inch in breadth.
A jeweller at Moscow is said to have had in his possession a
two-inch long Turquoise, of the form of a heart. This fornierly
belonged to Nadir Shah, who wore the same as an amulet, for
which he asked five thousand rubles.
A short time ago, I beheld one of the largest and most splendid
Turquoises at a sale, which was one inch in size, and of a blue
colour ; it is now in the possession of M. Livingston, Esq.
XLV. NATROLITE.
This mineral has been discovered of late years, and receives its
name from the Latin Natron, soda, given to it on account of that
alkali being contained in it ; it occurs reniform, botryoidal, and
massive, such as mamillary, and in alternate zones around the
centre ; it has a splintery firacture ; is translucent on the edges ; of
136 TREATISE ON GEMS.
a pearly lustre ; its colours are white, yellowish-white, or reddish^
brown, and they often alternate in different layers ; it scarcely
scratches glass, but is scratched by Felspar; has a white streak-
powder ; its specific gravity is 2.16 ; it fuses before the blow-pipe
into a colourless spongy glass ; it consists of soda, alumina, silex,
and water, sometimes a little oxide of iron. Its localities are
Switzerland, Bohemia, Saxony, Scotland, and Nova Scotia. The
Natrolite, on account of its susceptibility of a high polish, has
been Ui^ed for rings and other ornaments in jewellery, but has not
yet been in much demand, and its value is also very inconsiderable.
XLVI. FLUORSPAR.
This mineral was well known to the ancients, but did not attract
particular attention until the sixteenth century, when it was intro-
duced as a flux. As early as 1670 the art of etching on glass by
means of Fluorspar was practised at Nuremberg.
Fluorspar occurs mostly in crystals of various forms, the princi-
pal of which is the octahedron with its varieties, the cube and the
rhomboidal dodecahedron ; also, massive and in specks ; it has an
uneven or splintery fracture ; is transparent or transluceut on the
edges ; possesses simple refraction of light ; a vitreous lustre ; its
colours are purple, red, green, yellow, gray, blue, and white, in aU
its various shades, from the violet to the rose-red.
ItBcratches lime, but not glass ; yields to the knife ; has a white
streak-powder; its specific gravity is 3.14 to 3.17; it becomes
electric by rubbing ; before the blow-pipe it fuses with ebullition
into an opaque globule, but with boi*ax, into a transparent glass ;
when pulverized and treated with heated sulphuric acid, it emits
fluoric acid gas, which is employed in etching on glass ; phospho-
resces when thrown on hot iron ; it consists of fluoric acid and
lime. From the variety and beauty of its colours, it is known,
when cut, in trade, under the various names of false Emerald, false
Amethyst, false Ruby, and felse Topaz according to the colour it
exhibits. It is mostly found in metalliferous veins, and very rarely
in the newer formations. Its localities are in Baden, Bohemia,
Saxony, St. Gothard, at Derbyshire and Devonshire, in England,
and the United States, in the last of which countries it occurs of
most beautiful colours in fine crystals ; from a late^liscovered locality
at Russy, in St. Lawrence county, State oi New York, I have
TREATISE ON GEMS. 137
specimens of crystals two feet long and five wide. It is found in
Illinois, seventeen miles from Shawneetown ; Blueridge, Maryland ;
Smith county, Tennessee ; at Franklin Furnace, and Hamburgh,
New- Jersey; Saratoga Springs, and at Alexandria, New- York;
Middletown and Huntington, Connecticut ; Thetford and South-
hampton lead mines, Massachusetts, and on the White Mountains,
New-Hampshire.
Fluorspar is cut for ring-stones and shirt-buttons, and particularly
in such forms as are intended to be substituted for other gems ; in
Derbyshire there have been large mills for grinding, cutting, and
polishing the Fluorspar into vases, cups, obelisks, plates, candle-
sticks, &c, ever since 1765, and there are now more manufactories,
principally at Derby. That Fluorspar, which may be called the
nodular variety, and the colours of which run in bands or zones,
and which is known by the technical name of Derbyshire-spar or
Blue John, is used for various ornaments, to be met with all over
the world, in parlors or mineral collections. In order to heighten
the various colours in the ornamental specimens, before they are
polished, they are heated to a certain degree, when the dark spots,
or tints, disappear, and the coloured bands become more distinct.
Fluorspar is often intermixed with lead ore, called Galena, which
produces, when polished, a beautiful appearance. Ornaments of
Fluorspar still command a high price, which, however, depends a
good deal on the perfect qualities of the various specixnens, their
colour, size, &c.
A translucent variety of Fluorspar, called Chlorophane, found in
Cornwall, England, in Siberia, and principally in the United States,
at New Stratford, Connecticut, is of beautiful variegated colours,
but principally blue, violet, and green ; it is chiefly interesting on
account of its phosphoresence ; when put on hot iron in a dark
room, it emits a most beautiful emerald green light. One of the
first localities of Chlorophane discovered in this country, was at
Seekonk, Massachusetts, near the summer residence of the Hon.
Tristam Burges, about one and a half miles from Providence. It
is massive, opaque, and of a deep purple colour. It phosphoresces
readily on being projected upon a moderately heated shovel, when it
loses its colour and becomes white. It also occurs of a crystalline
structure in Wrentham, Massachusetts, near the Cumberland and
Rhode Island Une in the vicinity of Diamond Hill. A beautiful
s
138 TREATISE ON OEMS.
vase of Derbyshire-spar may be seen in the collection of the New-
York Lyceum of Natural History, as abo crystalline groups.
XLVII. MALACHITE.
The name of this mineral is from the Greek, alluding to its
colour ; it was well known to the ancients ; Theophrastus called it
the Pseudo Emerald ; it was worn by many as an amulet
It occurs tuberose, globular, reniform, mamillary, and stalacti-
form ; also, in fibres ; it has an uneven conchoidal, and splintery
fracture ; it is opaque ; of a dull and shining lustre ; and has an
Emerald or verdigris-green colour, alternating sometimes in stripes
of different shades of green. It scratches lime, but not glass ; its
streak powder is of lighter colour than the mineral ; its specific
gravity is 3.67 ; before the blow-pipe, it decrepitates and turns black ;
with borax, it is reduced to a metallic grain ; it effervesces with
nitric acid ; is dissolved, and forms a blue colour with ammonia ;
and it consists of oxide of copper, carbonic acid and water.
The Malachite is found in various rocks, primitive as well as
secondary, on gangues and strata. The finest specimens are
obtained in Siberia, Tyrol, France, Hungary, Norway, Sweden,
England, Bohemia, and the United States, at a great number of
localities, but either in small specimens, or as a coating of other
copper ores, which will ever render it useless for ornamental purpo-
ses. The principal localities in this country are in New- Jersey,
Connecticut, and at the various copper-mines ; it is also found in
the Island of Cuba, from which place I have seen some good
compact specimens.
Some very fine specimens of compact Malachite from Siberia,
were presented to the New- York Lyceum of Natural History, by
Charles Cramer, Esq., of St. Petersburg. I have also seen some
excellent specimens of Malachite in the collection of Dr. Martin
Gay, at Boston.
The Malachite, when cut, takes a high polish, which well
adapts it for various ornaments, such as rings, pins, ear-rings, &c.
Likewise snuff-boxes, candlesticks, mosaics, &«. are made from it.
In general the specimens are assorted, and the best pieces cut on a
leaden wheel with emery, and polished with rotten-stone on a tin
plate. Very large specimens are used for table plates and vases.
The value of the Malachite is not high, being very abundant ;
TREATISE ON OEMS. 139
yet much depends upon the size of the various specimens. At St
Petersburg, a very large slab, said to be in the collection formerly
belonging to Dr. Guthrie, thirty-two inches long and seventeen
inches broad, and two inches thick, was valued at twenty thousand
francs. Many rooms in several European palaces are laid out
with Malachite ; and the Mineralogical Museum, at Jena, possesses
the largest collection of Malachite I have ever seen, which was
presented by the Grand Duchess of Saxe Weimar, a Russian
princess.
An apartment in the Grand Trianon, at Versailles, is furnished
with pier and centre-tables, mantel-pieces, ewers and basins, and
enormous ornamental vases of Malachite, the gift of the Emperor
Alexander to Napoleon.
XLVIII. SATIN SPAR.
This mineral occurs stalactiform, globular, reniform and mas-
sive ; it is of a fibrous texture, (that is, of fine delicate fibres
closely adhering together), a pearly lustre, and is translucent on
the edges : the colours are, snow-white, yellowish-white, or pale-
red, coloured by metallic oxides. It scratches gypsum, but not
glass ; has a specific gravity of 2.70 ; becomes electric by rubbing;
before the blow-pipe it is infusible, and changes into quicklime,
but borax reduces it to a clear glass. It effervesces and dissolves
with nitric acid ; and consists of lime and carbonic acid. Satin
Spar is called by mineralogists fibrous limestone, and is found in
the coal formations, and in the cavites of several limestones.
The finest specimens are found in Cumberland and Derbyshire,
England ; in Hungary, and in the United States, near Baltimore,
in Pennsylvania, also at Westfield and Newburyport, Massachu-
setts, where spendid specimens five inches long are obtained,
according to Professor Hitchcock. It takes a fine polish, and is
distinguished by its extraordinary fine satin lustre, and is therefore
used for various articles in jewellery, such as ear-rings, necklaces,
beads, and also for inlaid work; large specimens are used for
snuff-boxes.
Satin Spar beads have been a great favourite as necklaces and
ear-rings, and were sold a few years ago in England at very high
prices. In modern times, the satin beads or pearls have been
imitated to a gcesx extent in France and Germany, in white and
140 TREATISE ON GEMS.
deep-yellow colours: glass beads, of a bluish-white tinge, and
hollow, are made to imitate the reflection of the Satin Spar, by
means of the scales of a small river fish called the bleak, that are
suspended in dissolved isinglass, and dropped into the bulbs, which
are then turned in all directions in order to spread the solution
equally over their interior surface ; in this way the glass bulbs
assume the natural colour and brilliancy of the Satin Spar ; they
are harder, however, and it is easy to detect them on that account.
Fine specimens may be seen at the New- York Lyceum of
Natural History, also, in the collection of Dr. Gay, of Boston.
The Satin Gypsum, which bears the greatest resemblance to
the Satin Spar, and only differs in its chemical constituents,
(having sulphuric acid, instead of carbonic, as a component part,)
is much used for the same kind of ornamental purposes, and is
more abundant over the world. I have seen very splendid speci-
mens at South Boston, in the beautiful collection of minerals
belonging to Francis Alger, Esq., who brought them from Nova
Scotia, and who (as also Dr. C. S. Jackson,) has given so valuable
a description of all the mineral treasures of that Province.
The Satin Gypsum is, however, much softer than the Satin Spar,
and is much easier scratched ; for which reasons it is not so
generally employed.
XLIX. ALABASTER.
This mineral is a compact Gypsum, and occurs massive, with a
compact fracture ; it is translucent ; has a glimmering lustre, and
its colours are white, reddish, or yellowish.
The purest kinds of this mineral are used in Italy for vases, cups
candle-sticks, and other ornaments. It is found at Castelino, in
Tuscany, thirty-five miles from Leghorn, at two hundred feet below
the surface of the earth.
The yellow variety is called by the ItaUans, Alabastro Agatato,
and is found at Sienna ; another variety of a bluish colour, is
obtained at Guercieto, and is remarkably beautiful, being marked
with variegated shades of purple, blue, and red. The above Ala-
baster^ are carbonates of lime.
The principal manufectory of Alabaster ornaments is at Val-
terra, thirty-six miles from Leghorn, where about five thousand
persons live by this kind of labour. In uiaking, they require great
TREATISE ON GEMS. 141
care^ and must be preserved from dust, as the Alabaster is difficult
to deau. Talcum, commonly called French Chalk, will remove
dirt, but the best mode of restoring the colour, is to bleach the
Alabaster on a grass-plat. Gum water is the only cement for
uniting broken parts.
Plaster of Paris is likewise a compact Gypsum, but contains
a small portion of carbonic acid, which makes it effervesce when
treated with acids. It was formerly only exported from Montmar-
tre, near Paris, hence its name ; it is much used in ornamenting
room^ in stucco, in taking impressions of medals, in casting statues,
busts, vases, time-piece stands, candelabras, obelisks, and for many
other purposes.
The common Plaster of Paris is ground after being calcined ;
and in this condition it has the property of forming a pliable mass
with water, which soon hardens, and assumes the consistency of
stone.
L. AMBER.
This gem was known to the inhabitants of remote ages ; the
Phenecians sailed to the Baltic, (the Glessany islands,) for the sole
purpose of obtaining Amber, which they wrought into chains and
other ornaments, that were sold to the Greeks, who called the
same Electrum. In the Trojan war, as Homer reports, the
women wore necklaces of Amber. Its electric properties were
likewise known, for Thales was so much surprised at that phenom-
enon, that he attributed it to a soul in the Amber ; and Pliny says
that Amber is revived by heat, the nature of electricity not being
understood. It was also worn as an amulet, and used for medicine.
The ancients could not agree as to its origin ; Philemon, according
to Pliny, classed it as a fossil ; Tacitus, however, judging from
the insects held in it, concluded it must be a vegetable juice,
whence its name in Latin, succinum, or juice. Many naturaUsts
have, until lately, considered Amber as a mineral ; but it has been
satisfactorily proved by Schweigger and Brewster, from its chemical
characters, and polarising light, to be a gum-resin, and that it is
the juice of a tree, called the Amber-tree, now extinct.
Amber occurs in nodules or roundish masses, from the size of
grains to that of a man's head ; and somethnes in specks ; it has
a conchoidal fracture; is transparent and translucent; possesses a
142 TREATISE ON GEMa
single refraction of light; a resinous lustre in a high degree: its
colours are wine and wax-yellow, greenish or yellowish white, or
reddish-brown ; sometimes the colours vary in layers. It scratches
gypsum, but is attacked by carbonate of lime ; its streak-powder
is yellowish-white ; it has a specific gravity of 1.08 to 1.10 ; it
becomes electric by rubbing. Before the blow-pipe it bums with a
yellowish and bluish-green flame, emitting at the same time a
dense and agreeable smoke, and leaving a carbonaceus residuum ;
heated oil softens and makes it pliable ; it does not melt as easily
as other resins, requiring 517** Farenheit ; it yields by dry distilla-
tion an acid which is called succinic acid, also an essential oil,
known by the name of oil of amber, and in the retort remains a
brown mass, called the resin of amber, which is used in the arts
as amber-varnish ; any essential oil, or spirits of turpentine may
be used for procuring the resin ; fat oils dissolve the Amber perfect-
ly ; its elementary constituents are carbon, hydrogen, and oxygen,
with some lime, alumina, and silex.
Amber is found either thrown up by the sea, or in the small
rivers near it ; sometimes in alluvial deposits of sand or gravel in
the vicinity of the sea or in bituminous formations, such as lignite,
bituminous wood, or jet, where crystallized minerals are at the same
time found, such as iron pyrites, &c.
Its geological distribution is in the green sand formation, or
according to De la Beche, the stratified rocks, between the third
and fourth large group. It is found all over the world, but the
principal localities are the shores of the Baltic, in Prussia, firom
Memel to Dantzic, where it is collected by the inhabitants in various
modes. One of the largest specimens ever met with on the Baltic
was found in 1811, measuring fourteen inches in length by nine
inches in breadth, and weighing twenty one pounds.
I had in my own collection, in the year 1831, a splendid wax-
yellow Amber, from the Baltic, which measured about sixty cubic
inches, and weighed nearly two pounds. It is also found on the
Danish coast, and in Greenland, Sicily, Monrovia, Poland, France,
and the West Indies. A sailor is said to have found a remarkable
specimen, eighteen inches in length, in a singular manner ; the
discoverer accidentally seated himself on it, when he became so
attracted to the Amber, excited by his natural heat, that it was
with some difficulty he could detach himself from it*
TREATISE ON GEMS. 143
In the United States we find Amber at Cape Sable, in Mary-
land, in a bed of lignite, in masses of four and five inches diam-
eter ; also, near Trenton, and at Camden, New- Jersey, where a
transparent specimen, several inches in diameter, was found.
According to Professor Hitchcock, it is found at Martha's Vineyard,
Gay-head, and at Nantucket. At the latter place, a light coloured
specimen was found, of three or four inches diameter, which is in
the collection of T. A. Green, Esq., of New-Bedford.
The production of Amber depends upon the position of the
respective localities ; whether it is found among sand and gravel, in
mines called Amber mines, or in the sea, on the shore, or in smaller
rivers near the sea coast ; and tlie modes of collecting arethree-fold :
1. The Amber mines, which are numerous in Prussia, are
wrought like other mines, and explored to a depth of more than
one hundred feet. Shafts are constructed for raising the product
from the interior of the mines ; the miners dig until they reach
the Amber vein, which is generally found after passing a stratum
of sand and a bed of clay of twenty feet thickness, and another
stratum of decomposing trees or lignite, which may be fifty feet
through ; they come then to the pits, which the characteristic colour
of the soil is the best indication to search for.
2. The second mode of collecting Amber, is practiced generaUy
after a storm, by the fishermen, who either wade into the water,
provided with leather dresses, to their necks, or use small boats,
and find at the depth of three fathoms the floating Amber.
3. It is mostly, however, collected in large quantities on the
shore, after having been thrown up by severe storms.
The Amber fishermen are, by practice, pretty well skilled in
finding out the spots where the largest quantities may be obtained.
Amber from the mines does not essentially differ from that of
the sea, excepting that the former is rather more brittle, and is
often covered with an earthy crust.
The Amber is assorted before it comes into the hands of the
lapidary or merchant, and according to size and clearness of colour,
it receives different technical names ; thus there are —
1. The exquisite specimens, which are perfectly pure, transpa-
rent and compact, weighing from five to six ounces or more ;
these are employed in larger ornaments and specimens of the arts,
and fetch the highest price.
144 TREATISE ON GEMS.
2. The to7i stones, which weigh from a quarter of an ounce to
four ounces ; the largest or purest pieces of which are used for
jewellery, and the impure for incense or medicine.
3. The nodules are still smaller.
4. The varnish stones are still smaller than the former, but are
very pure and hard, so as to be easily pulverized, and are used for
varnishes, sealing-wax, &c.
5. The sandstones are very small, opaque, and perforated
pieces.
6. The lumps are large but impure specimens, unfit for a lapi-
dary's use ; they are sold as specimens, or employed as incense or
for the manufacture of succinic acid.
7. Refuse are those pieces which fall off at the lapidary's bench.
The pure Amber receives from the lapidary distinct names,
according to the shades of colour it possesses, such as egg, pale
and light-yellow, and so into its brownish shades. The assorted
Amber is treated according to the various purposes it is intended
for, and receives its requisite form by cleaving with an appropriate
instrument, by which, also, the external crust is removed. It is
generally believed that the worse the crust is in appearance, the
more beautiful is the interior of the Amber.
Amber, taking a very high polish, is employed for a great many
purposes of jewellery, and for various ornaments, such as beads,
necklaces, bracelets, ear-rings, buttons, rosaries, mouth-pieces for
pipes, cane-heads, snuff-boxes, work-boxes, &c. It is generally
wrought on the turner's lathe, by steel instruments, and is easily
bored ; it is polished on a leaden wheel, with pumice-stone, then
with linen or a hat-body and rotten-stone, and lastly by rubbing it
with the hand. Common specimens are polished with a linen rag,
chalk and water. Beads of Amber must be drilled before receiving
the facets. In cutting and working Amber, care must be taken
not to overheat it by friction, as it will then be liable to crack.
Amber has occasionally been cut into cameos, busts, images, &c.
Impure Amber pieces may be much improved by wrapping them
in paper and allowing them to digest for forty hours in hot ashes, in
a pot filled with sand ; or by boiling them with gradually increased
heat in linseed oil. Amber may also be coloured red, blue and
violet, and dissolved in absolute alcohol ; it may be cast into diffe-
rent ornaments. Broken Amber may be mended by a cement of
TREATISE ON GEMS. 145
lioseed oil, gum mastic, and litharge ; or by moistening the ends of
both pieces with potash, warming the same, and pressing the parts
together.
The price of Amber was in former times ^ much higher than at
present, but size, colour and transparency always govern the same.
A pure exquisite specimen of one pound is sold for forty dollars ;
but most good specimens are sent to Armenia, the East, and Tur-
key, to which places manufactured Amber goods to the amount of
fifty to sixty thousand dollars are annually exported from one
manufactory at Stolpe, in East Prussia.
Amber is often adulterated in various ways, and more especially
with gum copal, which is palmed upon the ignorant for Amber, and
which does actually resemble it in many respects : for both are of
the same colour ; both become negatively electric by friction ; both
have nearly the same specific gravity ; and both give a pleasant
odour in burning ; hence when wrought as jewellery or ornaments,
it is not easy to distinguish the one from the other. One mode of
detection was pointed out by the Abbe Haiiy : " If," says he, " a
fragment of Amber be attached to the point of a knife, and infianied,
it will burn with some noise, and a kind of ebullition, but without
liquifying so as to flow : and if it should fall on any flat surface it
rebounds a little ; whereas the copal, under similar circumstances,
melts and falls in drops, which become flattened." My own expe-
rience has taught me the following distinguishing characteristics :
first, the electro-metre, a small instrument composed of a brass
needle, suspended on a pin, is the most essential distinguishing
guide ; for Amber, on being rubbed, will excite the instrument
about ten degrees more than copal ; secondly. Amber on being
brought before the fire, requires pretty high temperature for melting
it, and exhibits no kind of ebullitiou ; whereas copal easily liquifies,
burns with much smoke, and decrepitates more than Amber.
Amber is likewise adulterated by gum Arabic, gum thus, shellac,
and glass pastes. The last can easily be distinguished by their
hardness, and the others by their solubility in hot water.
Amber very frequently has inclosed within it insects, such as
flies, beetles, (fcc. in a state of complete preservation. Such speci-
mens are much sought for, and command a wevy high price ; and
on that account the adulterations are mostly practised, and in the
following manner: eitlier by boring a hole in the Amber and
T
146 TREATISE ON GEMS.
introducing the beetle and filling it up with pulverized gum mastic,
and then letting it melt over a charcoal fire ; or by melting the
Amber, throwing in the insects and letting it cool. The former
adulteration may easily be detected, since the mastic will never be
able to combine closely with the Amber, and shows more or less
cracks and fissures ; but the latter is scarcely to be detected, without
a scientific investigation of the inclosed insects, which in the natural
specimens do not exist in the present world, being called antedi-
luvian, or extinct species of animals.
The most extraordinary collection of specimens of Amber may
be seen in the cabinet at Dantzic. A specimen of Amber of fifteen
pounds weight is preserved in the cabinet at Berlin. The inhabi-
tants of Colberg, in 1576, presented to the Emperor Rudolph II. a
specimen weighing eleven pounds.
LI. JET.
This mineral occurs massive ; has a conchoidal fracture ; is
opaque ; has a shining lustre ; and Is of a jet, velvet, or pitch black
colour. It is pretty soft, and yields to the knife ; has a specific
gravity of 1.29 to 1.35 ; it burns with a greenish flame, and emits
a strong bituminous smell. In trade it is also called Black Amber
or Pitch Coal. It is found in the brown coal formation, of the
plastic clay, and the lias, with lignite and amber, in England,
France, Silesia, Hessia, Italy, Spain and Prussia.
Jet beara a high polish, and is wrought into necklaces, ear-rings,
crosses, rosaries, snufif-boxes, buttons, bracelets, and particularly
mourning jewellery. It is at first generally assorted to select the
best pieces, most suitable for working ; such as are free from iron
pyrites, lignite, and have no cracks nor fissures. It is then turned
on a lathe and likewise on horizontal sand stone wheels, which run
unequally on their periiphery, by which the various specimens may
be cut and polished at the same time. During the operation the
Jet must be moistened with water, else it may crack from being
overheated. It is polished with rotten-stone or crocus martis and
oil, on linen, or buckskin ; and lastly by the palm of the hand.
The manufacturing of Jet ornaments was formerly a considerable
branch of industry in France, where, in 1786, the department de
TAube occupied 1200 workmen ; but at the present time it is no
more worn, and the black enamel in substituted for it
TREATISE ON GEMS. 147
LII. CANNEL AND ANTHRACITE COAL.
Both the above species of coal are employed, like the Jet, for
ornaments ; the former is manufactured in England into various
ornaments, and the latter in the United States. At a late fair of
the American Institute, at New- York, large candlesticks and
various ornaments, made of anthracite, were exhibited, from a
manufactory at Philadelphia ; they were beautiful specimens.
LIII. LAVA.
This mineral is a compound of several minerals, and is a volca-
nic production. It occurs massive, with vesicular or porus marks ;
has a splintery and conchoidal fracture ; a lustre dull or glistening ;
is opaque, and of gray, brown, red, yellow, black, green and white
colours, of all their shades. It often contains crystals of Felspar,
Leucite, Hornblende, &c. In the arts for ornamental purposes the
compact varieties, only, are cut and polished. In Naples, jewellery
and ornaments in great quantities are manufactured and exported ;
such as pins, ear-rings, intaglios, snuff-boxes, vases, candelabras,
&c. The different Lavas are cut with sand and emery, and
polished with pumice-stone. Lava is found in all volcanic countries,
and particularly at ^tna, Vesuvius, Hecla, in Mexico, the Lapari
Islands, (fcc. Lava is often used as the base for Mosaic works.
The blue Lava of Mount Vesuvius has the appearance of artificial
blue enamel, and is in much demand for jewellery and ornaments.
I have inspected fine specimens of polished slabs at the rooms
of the Boston Society of Natural History.
LIV. JADE.
This mineral is called in Mineoralogical works Nephrite, Hatchet-
Stone, Punamu. It occurs massive; has a splintery fracture ; a
greasy lustre when polished ; it is translucent ; scratches glass,
and is attacked by Felspar ; it is of mountain-grass and sea-green
colours ; is fusible into a greenish glass ; it consists of silex, lime,
alumina, magnesia, and iron. It was originally found in China ;
it occurs in Egypt, on the Amazon river, in an island in New-
Zealand, called Pavia Punamu, and in the United States, (Smith-
field, R. I. and Newbury, Mass.)
It is used for snuff-boxes, cups, &c ; and in Turkey they use it
for handles to sabres, daggers, and hatchets. Deities formed of it
148 TREATISE ON GEMS.
have frequently been excavated from ancient ruins. Such I saw
a few years ago in a coDection of Indian curiosities brought from
Mexico.
LV. SERPENTINE.
This mineral derives its name from its vari^ated colour, which
resembles the skin of a serpent It is generally divided into two
varieties, the Common or Opaque Serpentine, and the Precious,
Noble or translucent Serpentine.
Serpentine occurs massive ; the common is occasionally crystal-
lized in rhomboidal crystals, in Norway, New-Jei-sey, and Penn-
sylvania ; it has a splintery, uneven and conchoidal fracture ; is
unctuous to the touch ; yields to the knife ; its colours are green
in all its shades, but also reddish and grayish ; it has a specific
gravity of 2.5 ; is infusible before the blow-pipe, but with borax
dissolves into a transparent glass. It does not belong to the strati-
fied rocks, but to (he ophiolithes of Brc^niart, and is mo^y associ-
ated with granite, gneiss, micaceous, chlorite, argillaceous shistes
and limestone ; and therefore belongs to the primilime formation.
Serpentine, for richness and variety of colours, exceeds all other
rocks; and it abounds all over the globe, in large consolidated
masses. Its localities are too numerous to be specified. In the
Alps, we find the Serpentine nine thousand feet high ; in FrancCi
the mountains of Limousin ; in Spain, Norway, Sweden, Scotland,
the Shetland Isles, England, Italy, Bohemia, Saxony, Bavaria,
and Switzerland ; in the United States we find it all along the
Alantic coast, where the primary rocks are found, as at Hoboken,
(New- Jersey,) opposite to New- York city, Warwick, (New- Jersey,)
as far as Maryland, at Bare Hills, through Pennsylvania, Rhode
Island, Connecticut, MassachuseUs, Vermont, d&c. The Serpentine
beds of Massacusetts are inexhaustible. In Middlefieid, Massa-
chusetts, the bed is one quarter of a mile in breadth and six miles
in length, which alone would be sufiicient to supply the whole
world with a valuable material for ornamental and architectural
puiposes. There are beds at Westfield, Blanford, Pelham, Zoar,
Windsor, Marlborough, Cavendish, and other towns in Vermont
Most beautiful specimens are found in Newbury, near Newbury-
port ; and latterly a new locality was discovered by Dr. Jackson,
in Lynnfield, Mass.
TREATISE ON GEMS. 149
Serpentine incloses the chromateof iron in the Shetland islands,
Maryland, &c. ; and is on that account of the highest importance
to the artist.
It is easily wrought on lathes into various articles; such as
snuff-boxes, vases, ink-stands, &c ; In a small place at Zoblitz, in
Saxony, several hundred persons are constantly employed in the
manufocture of boxes, trinkets, and chimney-pieces. The locality
at Grenada, in Spain, has supplied many churches and palaces of
Madrid with large columns, and other ornaments. It is really
surprising that the inhabitants of those districts where the Precious
Serpentine is found, have not yet employed it as an article of
trade, as the quality of the American Serpentine is, if not superior
to the English and Spanish, certainly not inferior to any hitherto
found: and I trust that the day is not far distant when our
parlours will be embellished with mantle-pieces, tables, and mantle
ornaments, made of it. Candlesticks, mugs, pitchers, knife-
handles, firearm-stands, jamb-hooks, and many other domestic
articles, instead of silver-plated, steel, and cast-iron ware, n)ight be
formed of it and used.
Serpentine is often associated with a number of other minerals,
thus : a. Serpentine with Talc ; 6, Serpentine with Diallage or
Schiller-spar; c. Serpentine with Amianthus; rf, Serpentine with
Asbestos ; e, Serpentine with Garnets ; /, Serpentine with Actinolite,
&c. That variety which contains the Amianthus in a layer, is
sometimes exceedingly beautiful ; and when polished has the
appearance of Satin-spar.
LVI. MARBLE.
This is the name of a very extensive family ; and although in
the form of limestone it is used as a buildirig material, it would not
receive a place in these pages, but that a number of species or
varieties are, for their beauty, structure and rarity, used in jewellery
as ornaments. I will, therefore, out of the large class embracing
Marble, limestone, and calcareous Spar, enumerate those varieties
which legitimately belong to our subject.
LVII. STALACTITE AND STALAGMITE.
It occurs in large tuberous, undulated masses, botryoidal, mam-
millary or concretional, either in icicles or circles ; has a fibrous
150 TREATISE ON GEMS.
fracture ; is translucent ; of a pearly lustre ; colour generally
yellowish-white and white ; its composition is calcareous spar ; it
originates in caverns, through which water, holding this in solution,
filters, and on its ultimate evaporation leaves the carbonate of lime
in various forms, which sometimes resemble altai*s, pillars, anunals,
&c.
Those pillars or icicles which are pendant from the roof, and
those rising from the base, are sometimes divided into Stalactite for
the former, and Stalagmite for the latter. But the cause of tlieir
existence is the same, and there ought not to be any distinction in
their name.
Ornaments of Stalactite in the shape of vases, (fcc. are often seen
in fancy stores. The greatest localities of this mineral are, the
Grotto of Antiparos, and Bauman's Cave, in the Hartz, which I
visited in 1827, and which displays giganticS talaclites ; also at
Derbyshire. In the United States, are very celebrated caves,
which yield this article.
These have lately been described by my friend Charles Cramer,
Esq. Russian Vice Consul at New York, an enthusiastic and
useful mineralogist, of St. Petersburg, in a pamphlet published
by the Imperial Minerabgical Society of St. Petei*sburg, in the
German language ; and as this interesting little work is not
accessible to all, I will here translate the list of all the caves enu-
merated by him as North American. We would observe that
these are not all situated in limestone regions, neither do they all
furnish Stalactites.
Canada — Grotto in the Niagara,
A cave in Lanark, Upper Canada,
A smaller cave at the same place.
New Hampshire — The Devil's Cave.
Vermont — The caves in Bennington,
" " Dorset.
Massachusetts — The Natural bridge and cave at Nahant,
" " over the Hudson brook,
The cave near Sunderland,
" in Berkshire,
Two caves near New Marlborough,
The cave near West Stockbridge,
" in Lanesboro',
TREATISE ON GEMS. 151
The cave in Adams,
The Purgatories, near Sutton.
Connecticut — The West Rock cave, New Haven.
Rhode Island — The Purgatory, near Newport,
The Spouting cave, near ditto.
New York — Cave near Watertown,
" at the Niagara,
Ball's Cave,
Knox's Cave,
The Mouito, at Wigwam, or Devil's Abode,
Esopus Cave.
Pennsylvania — The Devil's Hole, in Bucks county.
The cave on the Swatera river.
Maryland — ^Hughes' Cave,
The cave at Harwell.
Virginia — Weyer's Cave,
Wreast's Cave,
Madison's Cave,
Zane's Cave,
Blowing Cave, near the Panther Dale,
Green briar's Cave,
Cave on the Kanhawa River,
Cbapin's Cave,
Johnson's Cave,
Allen's Cave,
Ruffuei-'s Cave,
Roger's Cave,
Reid's Cave,
Natural Tunnel in Scott County,
Natural Bridge in Rockbridge County.
Ohio — Mason's Cave,
Nature's Building, or Cave in the Rock.
Indiana — Epsom Salt Cave,
Cave near Corydon.
Kentucky — Boone's Cave,
Russel's Cave,
White Cave,
Mammoth's Cave,
Gave on the Crooked Creek.
152 TREATISE ON GEMS.
Tennesee — Big-bone Cave,
Arched Cave.
South Carolina — Great Flat Rock Cave,
Lover's Leap.
Georgia — Nicojack Cave.
Missouri — Ashley's Cave.
Mississippi — The Abode of the Great Spirit on the North West
Coast,
Cave on the Copper River.
Mexico — The Dantoe Cave,
Chamacasapa Cave,
San Fillipe Cave.
Cuba — The Cave near Matanzas.
Ilayti — The Cave near St. Domingo.
Peru — The Cave in the Andes.
New Andalusia— lihe Canipe Cave.
Mr. Cramer mentions the size of the Stalagmites in the ante -
chamber of Weyer's Cave, as being twelve feet high ; thoee in
Solomon's Temple, of the same, twenty-five feet high, which are
nearly transparent ; and its Hermit Chandelier, four feet high, and
twelve feet in circumference ; the colossal Stalagmite in Washington
Hall, which is said to represent tlie father of his country wrapped
in his cloak; Pompey's column, thirty feet high; also Babylon's
Tower, thiity feet in circumference.
LVni. EGYPTIAN MARBLR
This is generally milk-white, or grayish-white and bluish, and
also black and red, which is called the Rosso Antico ; it is of a close
granular structure, and was a great favourite with the ancknt
architects.
LIX. ITALIAN MARBLES.
With these may be counted the Parian marble ; the Pentelian
marble ; the Venitian or Lombardy marble, which is quite translu*
cent; the Luni and Carara marble; and the Laconian marble, or
Verde Antica They have all yielded materials for themost ancient
Greek and Italian sculptors. The Venus de Medici, the Diana
hunting, and Venus leaving the bath, are of Parian marUe : a
Bacchus in repose, a Jason, a Paris, and many Grecian monu-
TREAllSE ON GEMS 153
ments, are from the Pentalian marble, which comes from the
vkiiiity of Athens.
LX. AMERICAN MARBLE.
The varieties of marble, which substance is inexhaustible in the
United States, are very numerous ; and I am proud to assert, that
for architectural and ornamental purposes, they will successfully
compete with those of any foreign country. The colours are
various, from the snow-white to the black with gold and grass-
green veins. A small district in New England, of about fifty miles
in extent, concentrates, I may say, the marbles which may be
collected in Europb through a space of two thousand square miles ;
for we find in the county of Berkshire, and that of New Haven, the
representatives of marbles from Italy and Ireland ; and the disco-
veries which are constantly making of additional marble localities
are a source of great satisfaction. Thirty years ago, the City Hail,
of New York city, was built of marble firom West Stockbridge,
Massachusetts, which was transported at great expense, a dis-
tance of over four hundred miles ; whereas, afterwards, the same
quality of marble was discovered on New York island, but a few
miles distant. According to Professor Dewey, the county of Berk-
shire alone turned out forty thousand dollars worth of marble
several years ago. I will here enumerate a few of the most interest-
ing marbles, such as —
a. The Philadelphia marble, which is snow or grayish white,
and sometimes variegated with blue veins, which takes a very high
polish.
6, The Potomac marble, which is properly called a breccia, being
obikiposed of rounded and angular fragments from the size of a pea
to that of an ostrich's egg. Its colours are red, white, gray, and
blackish-brown, intermixed ; it takes a very fine polish, and forms
a most beautiful ornamental stone. It comes from the banks of
the Potomac, in Maryland. As specimens of this, we would refer to
the columns in the House of Representatives at Washington, which
are twenty feet high, and two feet in diameter.
c, The Verde Antico, of New Haven, Connecticut. Thisr marble
is intermixed with serpentine veins, and makes a most beautiful
appearance. There are inexhaustible quarries of it at New Haven
ai^d Milford ; it bids &ir to rival every other lurnaaiental stone in
V
164 TREATISE ON GEMS.
the world. Four chimney-pieces of this mineral were purchased
for the Capitol at Washington ; and I lately examined a splendid
centre table, wholly cut from this marble, that was exhibited at the
tenth annual fair ofthe American Institute. It is to be hoped that
some company may undertake to introduce this marble more
extensively into notice, for it does not yet appear to be sufSciently
known among our wealthy citizens, and the enterprise would b6
well rewarded. Large slabs may be seen at the New York Lyceum
of Natural History, and in the cabinet of Yale College, New-
Haven ; I possess a very fine, large slab, polished. Portsmouth; Vt
likewise furnishes splendid Verde Antico, specimens of which may
be seen at the American Institute, in New York.
d^ Berkshire county, in Massachusetts, may justly be called the
marble pillar of the United States ; and, as Professor Hitchcock
remarks, 1 he inhabitants of that county cannot but regard their
inexhaustible deposits of marble as a rich treasure to themselves^
and an invaluable legacy to their posterity. The towns, West
Stockbridge, Lanesborough, New Ashford, Sheffield, New Marl-
borough, and Adams, in that county, keep thousands of hands
constantly working in their quarries. In 1827, two thousand
seven hundred tons of marble were exported from that town ; and
in 1828, a block of from fifty to sixty feet square^ and eight thick,
was raised by one charge of gunpowder.
e. White, fine, granular marble, bearing the closest resemblance
to the celebrated Carara marble, is obtained from Smithfield, R. I.
and Stoneham, Massachusetts.
LXI. SHELL MARBLE.
This mineral is a secondary marble, and is called also concbitic
marble, on account of its containing petrified shells, which, when
polished, communicate to their matrix, the marble, a most beauth^'
fully variegated appearance.
a. The Lumachelle marble is a kind which is very scarce ; it has
a gray or brown ground, interspersed with shells of a circular forfti
and golden colour, and when held towards the reflection of light,
displays red, blue and green tints, like those of the precious Opal or
iridescent Labrador:
It is sometimes seeti in the form of pinS^and ofih^r' jewellery ; but
stands, on account of its scarcity, very high in prioei the only
TREATISE ON GEMS. 165
Ideality is in Corinthia; one formerly in Devonshire, England,
being exhausted; * Some splendid* specimens frolm Corinthia, are
in the collection of the Baron de Lederer, Austrian consul of this
city; and a very fine specimen of the Lumachelle, at the Boston
Society of Natural History, was marked with the locality of
Neufebatel.
6, The Panno di Morto, or funeral pall, is a deep black marble,
with white shells, like snails, which is only seen at Rome, and is
very scarce.
Cj'The Bristol marble, from England, is a black marble, inter-
spersed with white shells.
rf, The Italian shell marbles from Florence, Lucca, and Pisa,
are red, containing white shells (ammonites).
c. The French shell marbles are very numerous ; those from
Narbonne are black with white belemnites ; that from Caen is a
brown marble with madreporites ; and those from Languedoc are
of a fiery red colour, mixed with white and gray univalve shells ;
of this Napoleon's eight columns for his triumphal arch in the
Carousel, at Paris, were cut.
/, The United States have a good many shell marble quarries ;
but they are all black and gray. Those of Trenton Falls, and
Little Falls near Seneca lake, Northumberland co. Pennsylvania,
Bernardston, Mass., and Hudsoti, N. Y., contain either trilobites or
encrinites ; some take a very fine polish.
LXn. PISOLITE AND OOLITE.
These minerals are likewise composed of carbonate of lime ; they
occur massive, and in distinct concretional layers, either in the form
of peas or other round grains or pebbles, and are of a white, yellow-
ish-white, brownish or reddish colour; when cut and polished, they
make a fine ornamental stonej and present a very effective appear-
ance. The former is found in alluvial deposites of the hot water
mineral springs of Carlsbad, in Bohemia, and the baths of St. Philip,
in Tuscany ; the latter forms large beds in England and France.
The city of Bath, in England, is mostly built of this limestone.
LXIII. THE ROCK OP GIBRALTAR.
This is likewise a carbonate of lime ; occurs massive, mostly
striped ; is yeUo wish-white, yellow, and ^ brownish ; is only found
166 TREATISE ON GEBi&
in that rock iromw hence it takes itis name, and has been heretofixe
a great favourite for jewellery and other ornaments. At this day
we see in the shops and private houses, pins, brooches, ear-rings,
seals, cane-handies, snuff-boxes, letter-holders, vases, uros^ candle-
abras, obelisks, &/C., formed of it. It takes a high polish.
LXIV. APATITE.
This mineral has its name fiom its colour, meaning decqithre,
as it resembles the colour of some more precious gems ; it occurs
in six-sided prisms, has a conchoidal fracture, a vitreous lustre, is
translucent, and yields to the knife ; its colours are white, yellowish-
white, greenish-yellow, blue, bluish-green, grass-green and reddish.
It resembles the beryl and emerald, but is distinguishable by
colour and hardness ; it is found in primitive rocks ; its locaUties
are met with all over the world, but most abundantly in the United
States. Specimens of three or four inch crystals from Etonville,
N. Y., have a spendid appearance, and if cut and polished, would
make fine pins, ear-rings, and other ornaments and jewellery.
LXV. LEPIDOLITE.
This mineral derives its name from the Greek language, from
its scaly structure ; it occurs massive, presenting an aggregate of
minute shining, flexible scales or hexagonal plates; it has a
splintery fracture ; a glistening and pearly lustre ; is translucent on
the edges; its coloui*s are lilac and rose-red, and pearl-gray,
greenish-yellow-and blue; it is scratched by glass, and yields to
the knife ; has a specific gravity of 2.81 ; is fusible with ease into
a transparent globule. It is found in granite and primitive lime,
in Monrovia, France, Island of Elba, Corsica, Sweden, and in the
United States, in Maine, New-Hampshire, Vermont and Massa-
chusetts. It is cut in Europe for various ornaments, such as
plates, vases, snuff-boxes, &c., and will, I trust, at some future
day, be more extensively used in jewellery ; for there are some
variegated specimens of a peach-blossom colour, and very fine
granular structure, which are extremely beautiful.
LXVI. MICA.
This mineral occurs crystallized, in six-sided tables and oUique
rhombic prisms, and massive; also, disseminated ; it has a perfectly
TREATISE ON GEMS. 167
foliated structure ; a glittering and metallic lustre ; is transparent
and translucent ; very AisiUe and elastic : its colours are, white,
green, black, brown, peach-red, yellowish and bluish ; it has a
specific gravity of 2.7. It is found in primitive rocks, and forms an
ingrediefitia granite, gneiss, mica slate, and other rocks, where it
moce or less predominates ; its localities are, therefore, universal,
bat in Siberia it forms large beds, and is quarried for special
purposes, such as a subtitute for glass windows ; and although the
United States afford ample localities of the same, yet a few years
ago quantities were imported here for the doors of Nott's stoves.
The Plumose Mica is a beautiful variety, and derives its name
from its resemblance to a quill or plume, the lamellar or jSne
delicate crystals diverging in such a manner as to present this
appearance. It is of a pearl-gray colour. It is found in the
United States, at Williamsbury, Mass., Hartford, Conn., and many
other places. The green Mica is of a beautiful grass-green
colour, and is found in Brunswick, Maine. The rose-red Mica is
a very beautiful mineral, and is found in numerous places, in this
country ; principally at Goshen, Chesterfield, Mass. ; Acworth, N.
H. ; Bellows Falls, Vt, &c. The Mica may, when of good
colours, be used for jewellery and other ornaments, as well as the
Lepidolite.
LXVII. PYRITES.
This mineral is called Sulphuret of Iron, Iron Pyriles, and
Markasite. It occurs crystallized in many forms; such as the
cube, octahedron, and dodecahedron ; also massive, disseminated,
capillary and cellular; it has a conchoidal fracture; a brilliant
metallic lustre; its colours are bronze, yellow, brass-yellow and
steel-gray. This mineral takes a very high polish, and from its
fine lusire looks extremely well when cut in the form of a brilliant
or rose. It was formerly much used in jewellery for ear-rings,
rings, pins, and necklaces. It was, in former times, considered a
great preservative of health. It is now but seldom seen, except
in mineralogical cabinets.
LXVIII. ROSE MANGANESE.
This mineral is called in mineralogical works the Siliceous
Oxide of Manganese, and also the Carbonate of Manganese. It
158 TREATISE ON aSM&
occurs massive ; has a foliated structure ; a conchoidal fracture ; a
shiniug lustre ; it scratches glass ; its colours are roee<red, reddish^
and yellowish.
It is found in Siberia, Sweden, Hungary, England ; and in the
United States, at Middlebury, Yt., and at Cummington and Plain-
field, Mass., where, according to Professor Hitchcock, the Biliceous
oxide, or according to Dr. Thompson, the bisilicate of Manganese
is found in great abundance. Since it takes a very high polish,
and is much wrought at Catharineburg, in Siberia, into many
ornaments, it is confidently to be hoped that it may also find its
amateurs in this country, as it is very easy to cut and polish, and
the material is so plenty.
LXIX. PORPHYRY.
This mineral form rocks in a geological sense, but is properly a
compact Felspar. It has various colours and shades, contains
imbedded crystals of Felspar and Quartz, or either of them, and is,
as may be supposed, a very hard stone. It is much used in Europe
for ornamental and architectural purposes ; also for slabs, mortars
and other articles.
In the United States, Porph)rry has never been used for any
purpose ; but Professor Hitchcock remarks, in his Geological Report
of the state of Massachusetts, that it would be strange if an
increase of wealth and refinement should not create some demand
for so elegant and enduring a rock as Porphyry. In the same
excellent work the author divides Porphyry into four v^ieties, as
occurring in Massachusetts, in the neighbourhood of Boston :
1st. Compact Felspar, with several predominating colours ; the
one with yellow, resembling the Turkey Stone; one with red,
from brownish to blood-red, closely resembling Jasper ; one with a
rose-red colour, resembling the Rose Petrosilex of Europe.
2d. Antique Porphyry ; closely resembling that European Por-
phyry which was employed by the ancients in monuments and
ornamental furniture and forms, and is when polished a beautiful
ornament. It presents numerous varieties and shades. of colour :
one of the most elegant is the light green ; then a deep green ; red
of various shades ; reddish-brown ; black, or nearly so ; gray and
purple ; and the imbedded crystals are uemally of a light colour,
sometimes white, brown, and greenish.
TREATISE ON GEMS. 159
r
3d. Porphyry with two or more minerals imbedded, and having
a base of common Felspar. This mineral is between Sienite and
Porphyry, resembling the Trachytic Poiphyry, and is generally
unfit for ornamental purpose; the Quartz which it contains is
hyaline and smoky.
4th. The Brecciated Porphyry, which is composed of angular
fragments of Porphyry and compact Felspar, reunited by a paste
of the same material ; the fragments are ^Iso of various colours,
usually, however, gray and red; the rock is very hard, and when
polished, furnishes specimens of great delicacy for ornamental
purposes.
LXX. SIENITE.
This rock is' compossed essentially of Felspar and Hornblende,
and sometimes contains Quartz or Mica, or both. When polished
it forms the most splendid ornamental stone of all other rockd ; it
is very hard ; and its colour and the mode of distribution of the
various ingredients, make it very agreeable to the eye. It much
resembles Granite, and is often almost identical with it : but by
close inspection it may be distinguished from the want or addition
of the component ingredients.
Professor Hitchcook describes six varieties of the Sienite :
1st. That Sienite which is composed of Felspar and Hornblende,
when the first is white, greenish, and yellowish, and the latter
invariably black.
2d. Felspar, Quartz and Hornblende ; the first is foliated, and
commonly of grayish, bluish or yellowish colour; the second from
quite light to dark colour and hyaline ; and the latter is black.
Under this variety the quarries at Quincy and Cape Ann have
been arranged by the author,'; (which are generally called Granite,)
on account of the absence of Mica. The Quincy Granite, or
rather Sienite, is that celebrated architectural material used in the
cities of Boston and New York, for those huge and magnificent
edifices, public as well as private, erected within the last six years ;
and it may be supposed that two thousand buildings in the city of
New York have been constructed with this splendid article.
3d. Felspar, Hornblende, Quartz and Mica. This rock, likewise,
has a beautiful appearance, but is, as yet, less wrought than the
160 TREATISE ON GEMS.
Other varieties. The Felspar and Homblende are predominant.
The duartz is in small grains, and the Mica is black.
4th. The Porphyritic Sienite ; its base is Quartz and Felspar,
and the Hornblende is almost entirely absent ; it has a porphyritic
aspect ; the F^elspar predominates. It is the most ornamental
stone when polished.
5th. Conglomerated Sienite ; it is a quartemary compound of
Felspar, Hornblende, Quartz and Mica, but all in rounded or
conglomerated masses, having the aspect of a pudding-stone ; the
nodules are from half an inch to six inches in size, and may be
easily broken out of the mass, and the Hornblende predominates
mostly in them. It is unfit for architectural purposes.
6th. The Augite Sienete ; in this rock the Hornblende is present
and Mica absent. It is composed of black Hornblende, greenish
Augite, and yellowish Felspar ; all, except the Felspar, presenting
a crystalline structure ; it is also composed only of Augite and
Felspar.
Tiie name of the rock Sienite was originally derived from
Sienna, in Upper Egypt, from whence the first specimen was
procured ; it was examined and identified by Werner ; many of
the Egyptian monun)ents, such as Cleopatra's Needle, and
Pompey's Pillar, were obtained from there.
LXXI. GRANITE.
This rock is composed of Quartz, Felspar and Mica, and forms
the crust of our globe. It occurs over the whole earth, and the
eastern part of the United States is abundantly furnished with this
valuable mineral. As a building material it has been most exten-
sively used for the last ten years ; but the great fire in New York,
which consumed, in December, 1835, seven hundred buildings,
among which about two hundred were erected of Granite, has
given a sufficient proof that Granite is, in this changeable climate,
unfit for a building material, but that it may be usefully employed
for ornamental and architectural purposes, where it is not constantly
exposed to the atmosphere and weather, which make it so Uable
to decomposition.
Nevertheless, Granite continues to be generally employed in the
erection of public buildings, warehouses, bridges, &c., and begins
to form an important pecuniary object to the mer^iam and
X"
' . ' >
TREATISE ON 6BM8. 161
mechanic; and on this account I cannot forbear to treat more fiiUy
on its general characters, and I must confess that the rich granite
treasures of Connecticut, Rhode Island, and Massachusetts, which
I had occasion to examine a few weeks ago, on my journey into
those regions, deserve fully all the enconiums bestowed upon them
in Hitchcock's Report on the Geology of Massachusetts, and in
Shepherd's Report on the Geolc^cal Survey of Connecticut So
abundant and large are the Grstnite rocks in the eastern • part of
the United States,* that some single localities are sufficient to
supply many countries with this lucrative article. Professor
Hitchcock divides the Granite of Massachusetts in four varieties,
viz:
1, The Common Granite, which, according to him, embraces
nine-tenths of the Granite, in Massachusetts, and the ingredients
are a distirtct crystalline structure, mixed and discriminating colours.
2, The pseudomorphous Granite is that variety in which the
mica separates distinctly (the "Other ingredients, which are closely
mixed.
3, Porphyritic Granite : it contains besides the usual composition,
of Q^uartz, Felspar and Mica, distinct imbedded crystals of Felspar.
4, Graphic Granite : this variety consists of Quartz and Felspar
only, the cross fracture presents the appearance of written charac*
ters.
Professor Shepherd divides the ornamental Granite of the State
of Connecticut into eight different types, viz:
1, Gray Granite.
2, White Granite. This variety I have examined myself a
week ago, in Plymouth, (Ct.) and so beautiful was its colour, and
close granular texture, that I took it at a distance for a sand-stone
or white marble.
3, Flesh-co!oured Granite.
4, Red Granite.
5, Epidotic Granite.
6, Porphyritic Granite.
7, Chloritic Granite.
8, Sienitic Granite.
In Rhode Island, a fine white Granite has, according to Dr.
* Professor Flitchcock remarks that there is not a town in Massachusetts in
which mor9 or less of Granite does not occur, either as situ or as boulders.
W
162 TREATISE ON 6EM8.
Webb, of Providence, been employed for the erection of the arcade
of that city, from a quary in Johnstone, five miles from Providence.
The manner in which the Granite is usually spUt out at the
quarries is this : a number of holes, of a quadrangular form, a
little more than an inch wide and two or three inches deep, are
drilled into the rock at intervals of a few inches, in the direction
in which it is wished to separate the mass. Iron wedges, having
cases of sheet iron, are then driven at the same time and with
equal force, into those cavities ; and so prodigious is the power
thus exerted, that masses of ten, twenty, thirty, and even fifty
and sixty feet long, and sometimes half as many wide, are
separated. These may be subdivided in any direction desired ;
and it is common to see masses thus split till their sides are less
than a foot wide and their length from ten to twenty feet.
The price of the Granite from these quarries, ax:cording toProfessOT
Hitchcock, is from forty to forty-five cents per superficial foot,
and for hammering and fine dressing it, about thirty cents the
superficial foot, such as in the style of the Tremont House in
Boston ; common work from twenty to thirty-five cents ; posts for
stone fronts cost thirty-four cents per foot. The enterprising
citizens of the city of New York have erected gigantic monu*
nneots of Granite for future generations to admire.
} ■
APPENDIX.
,«o»'
LXXII. PEARLS.
Pearls are concretions, consisting of carbonate of lime, having a
roundish, tubercular, or angular form ; a white, gray, blue or green
colour ; a shining lustre, and the hardness of lime. They are found
in several bivalve shells, particularly however in the Mother of
Pearl, {ovicula marga vitifera) ; abo in the oyster, and several
unios. The origin of the Pearl is by some considered to be unfruc-
tified eggs ; by others, a morbid concretion or calculus, produced
by the endeavour of the animal in the shell to fill up holes therein ;
by others again, as mere concretions of the juice of which the shell
has been formed, and with which the animal annually augments
it. It is very plausible, however, that the animal of the shell is
attacked often by enemies, such as the boring shells, (turritella,) &c. ;
that grains of sand, or any other pointed sub tance, which, on such
occasions, come within the shell, stick fast and augment with the
growth of the shell ; it is also know n that the Pearls may be
produced artificially, by pressing a sharp body on, or by boring a
hole in, the shell. The Chinese are in the habit of laying a string
with five or six small pearls separated by knots, inside of the shells,
when the fish are exposing themselves to the sun, and taking them
out after some years, whereby they obtain very fine and large
pearls, and but a little open on the side where they were adherent
to the shell. The pearl fishers say that when the shell is smooth
and perfect, they never expect to find any Pearls, but always do
so, when it has begun to be deformed and distorted. It was there*
fore concluded, that as the fish grew old, the vessels containing the
juice for forming the shell and keeping it in vigour, became weak
and ruptured, and from this juice accumulating in the fish, the
Pearl was formed, and the shell brought to decay, as supposed by
M. Reaumur. It would be, according to this idea, a sure guide
to know from the form of the shell, whether the Pearl is large or
small ; and thus by the smaller ones being thrown back into the
sea, a constant crop of large Pearls might be obtained. The mother
of Pearl fish is found in the East and West Indies, and other seas
164 APPENDIX.
in warm latitudes, and in the rivers of north and middle Europe.
In some parts of the globe, they are found in clusters, containing a
great number ; the places where found are called pearl banks. The
most famous are near the coast of Ceylon, that of Japan, and in
the Persian Gulf, near the island of Bahreim ; also near the coast
of Java, Sumatra, &c. The finest and most costly Pearls are
oalif^d the Oi^ntal ; and are from the above places ; they are all
tvhite or yeflowish ; those from the Perisian Gulf, on account of
their pei^fect whiteness, are preferred to those from Ceylon. Pearls
are collected in rivers with the hand, but in seas it is the business
of divers, brought up to this most dangerous occupation from early
youth. In the Bast Indies there are two seasons for pearl fishing ;
the first in March and April, the second in August and September ;
and the more rain, the more plentiful are the pearl fisheries. In
the beginning of the season there are sometimes two hundred and
fifty barks oil the banks ; the larger barks have two divers, the
mnall^r, one. The divers descend from their barks with a rope
round their body, and a stone of twenty or thirty pounds attached
to one of their feet, so that they may sink speedily fi^om eight to
twelve fkthoms, where they meet the shells festened to the rocks :
the nostrils and ears are stuffed up with cotton, and to the arm a
sponge dipped in oil is fastened, which the diver now and then
bluings to his mOuth, in order to draw breath without swallowing
water. He also carries down with him a large net, tied to his neck
by a long cord, the other end of which is fastened to the side of the
vessel, to hold the shells, and the cord is to draw hirn up when the
net is full, or when he wants air ; he has likewise a knife or an
iron rake, for detaching the shells from the rocks. Thus equipped,
he precipitates himself to the desired depth, where he can very
distinctly see all that is passing around, yet cannot escape in time
the sudden approach of sharks, to whom he too often becomes a
prey. When the diver has been in the water some minutes, and
has his net filled, or is unable tofitay any longer, he loosens quickly
the stone at his foot, shakes tbft line, and he is drawn up by his
companions. The diving-bell is now frequently used ; more so
than in former years.
In the Persian Gulf the divers rub their Ixxlies with oil, and
fasten a stone of about fifty pounds to their feet.
Th6 sheUs obtained are pil^d up in heaps, and toft exppgfMH6 the
APPENDIX. 165
rain and sun until the body of the animal putrifies, and tbey open
of themselves. Those containing any Pearls have from eight to
twelve. After being picked out, washed and dried, they are passed
through nine selves of different sizes.
At the Pearl islands, near the Isthmus of Panama and Colombia,
the pearl fisheries have, within a few years past, become lucrative
to some of the inhabitants. The divers use more simple methods
than those we have mentioned, for collecting the pearl oysters :
they traverse the bay in canoes that hold eight men, all of whom
dive naked into the water, from eight to ten fathoms deep, where
they remain about two minutes, during which time they collect all
they can with their hands, and dexterously rise to deposite them in
their canoe, repeating the operation for several hours.
In Sweden, they catch the pearl oyster with a pair of long tongs.
The fishermen are in small boats, painted white on the bottom,
which reflects the light to a great depth, and as soon as they
perceive them passing underneath they seize th^ oyster.
Pearls are esteemed according to their size, form, colour and
lustre ; the largest, of the size of a small walnut, are called para-
gons, which are very rare ; those the size of a cherry, are found
more frequently, but still are rare ; they are the diadem or head
pearls. They receive names, also, according to their form, whether
quite round, semi-circular and drum-form, or that of an ear-drop,
pear, onion, or as they are otherwise irregularly shaped, l^'he
small pearls are called ounce pearls, on accoudt of being sold by
weight, and the very smallest, seed pearls. Those of a brilliant
white colour, or white water, are most sought for in Europe ; those
of a yellowish colour in some parts of Asia ; and some of a lead
cobur, or those of a jet black, are preferred among some nations.
They all turn more or less yellow with age, and to restore the
white colour, they are either baked in bread, rubbed with boiled
salted rice, or kept for a short time in the gastric juice of fresh-
killed chickens.
Pearls are sold by weight, the Troy or gold weight ; but the
dwt. of twenty-four grains is counted as thirty ; so that an ounce
has six hundred grains, pearl weight, and four Troy grains are
equal to five pearl grrains. The price has, within the last forty
years, much diminished, for two reasons :
1st - Diamonds^ and particula^y brilliants, became more plenty,
166 APPENDIX.
and have siiice been worn, not by the higher classes alone, but
also by the middling.
2d. Within the last twenty years, artificial pearls have been
manufactured in high perfection, and are worn to a great extent.
It is my opinion, however, that the price of pearls will take a
fresh rise among the nobility and richer classes, the Diamond being
now so generally worn ; as persons, thinking to invest safely,
without any future loss, their surplus capital, purchase brilliants
that formerly were possessed exclusively by the rich.
Pearl fisheries were first carried on in remote times in the
Persian Gulf, and the most celebrated, formerly, were near the
island Bahreim. Five hundred thousand ducats was then the
yearly produce. About one million dollars worth, at the present
time, are exported. The island Kharack now produces the most
considerable quantity. The principal market is at Maskate ; from
thence they are brought to Surat. The mode of procuring them
pursued in those countries, is in canoes, holding fifteen men, six of
whom are divers : the shells caught during the day are delivered
to a surveyor, when they are opened on a white cloth, and
whoever finds one of some value, puts it in his mouth, to give it,
as they say, a " better water." The greatest harvests are generally
after many rains, and the largest Pearls are mostly found in the
deepest water. At Ceylon the pearl fisheries are now considerable,
particularly in the bay of Condeatchy. The shells are there lefl
to reach the age of seven or eight years, and in the fourth year
they have small Pearls, sometimes a hundred and fifty. They
fish yearly, in the month of May, during four weeks. In the
year 1804, eight hundred canoes, each with two divers, were
engaged. Belbre the year 1800, the pearl banks were leased, to
an Indian merchant, for three hundred thousand pagods ; and
before the arrival of the Europeans in India, the same bank was
used every twenty or twenty-four years ; when under the Portu-
guese, every ten, and under the Dutch, every six years. In 1800,
the produce was from one hundred to one hundred and fifty
thousand pounds sterling.
Japan has some pearl banks, which are, however, not much
sought, just like the Nipthoa lake, in Chinese Tartary. America
did send, in the sixteenth century. Pearls to the amount of eight
hundred thousand dollars, to Europe. The shells were ^mostly
APPENDIX. 167
collected from Cape Paria to Cape Yelo ; round the islands Marga-
rita, Cubagna, Cocher Punta, Aragy, and at the mouth of Rio
la Hacha, from which latter locality, and the Bay of Panama,
Europe is now mostly supplied ; the former locaUties having long
since been relinquished, on occount of their small produce ; too
many shells having been removed at one time, thereby retarding
the growth of Pearls. Panama has sent, within a few years past,
about one hundred thousand dollars worth of fine pearls to Europe,
the trade being carried on by Messrs. Plise, of Panama. The
coast of Florida is said to have been very lucrative to the Indians,
in a pearl fishery, winch, however, does not prove so now, since the
settlement of civilized people.
England used to be supplied from the river Conway, in Wales ;
and Scotland supplied the London market, between the years 1761
and 1764, to the amount of ten thousand pounds sterling ; but the
supply has failed. Pearls are found in the Elster river, in the
kingdom of Saxony, from its source at the borders of Bohemia to
Elsterberg, where the fishery has been carried on since 1621, with
some advantage to the sovereign ; some Pearls found there were
valued at fifty Prussian dollars each. In the river Watawa, in
Bohemia, and in the Moldau river, from Kruraan to Frauenburg,
Pearls are found of great beauty ; so much so as to equal in price
the Oriental Pearls. Also, at Rosenberg, Pearls are sometimes
found superior to the Oriental in lustre ; and at Oelsnitz, a con-
siderable pearl fishery is carried on. Most of the rivers in Sweden,
Lapland, Finland, Poland, Norway, Jutland, Silesia, and other
places, contain Pearls, but they are not collected.
The price of Pearls used formerly to be determined like that of
the Diamond, from one carat upwards, viz ; if the carat is fixed at
five dollars, and a pearl weighs four carats, take the square, or
sixteen multiplied by five, which is equal to eighty ; so that a Pearl
of four carats was estimated at eighty dollars.
I am informed by Mr. Plise, who has very recently brought a
consideraUe quantity of Peails from Panama, that he receives four
dollars per grain in England, for those of good size and quality.
A Pearl which Pliny valued at three hundred and seventy-five
thousand dollars of our money, Cleopatra is said to have dissolved
at a banquet, and drank off to Mark Antony's health. The Pere-
grine, which was found in 1574, near Margarita, and given to Philip
168 APPENDIX.
II. of Spain, was of pear-form, the size of a pigeon's egg, weighed
twenty-five carats, and was valued at fifteen thousand ducats.
Pope Leo bought a Pearl for eighty thousand crowns. Tavernier
describes one belonging to the King of Persia, which is said to have
cost one million six hundred thousand livres. Portugal has a
Pearl in its treasury of the size of a pear. JuUus Csesar bought a
Pearl from Servilia, the mother of Brutus, for one hundred and
fifty thousand crowns. Two Greeks, residing in Moscow, are in
possession of a Pearl weighing twenty-seven seven-eighth carats.
For restoring Oriental Pearls to their original lustre, which they
lose in course of time, the following process is resorted to in Ceylon :
the Pearls are allowed to be swallowed by chickens, which are
then killed, and the Pearls are an hour afterwards tak^n out of the
stomach, when they are as white and lustry as if just taken from
the shell.
ARTIFICIAL PEARLS.
Artificial pearls or beads are of various kinds ; most' generally
they consist of solid masses of glass, with a hole drilled in them ;
or they are blown hollow, and then filled out with metallic lustry
grains, wax, or with the fine scales of the bleak fish, which have
a silvery and pearly lustre. The same scales are likewise used to
coat beads of gypsum, or alabaster, which are soaked in oil and
then covered with wax to give them a pearly appearance. The
Roman beads are made in this manner ; the scales are diseolved
either in liquid ammonia, or vinegar, and the solution or liquid is
used for covering those artificial beads. The Turkish rose heads
are made of an odoriferous paste, and are turned afterwards like
those of coral, amber, agate, or other hard substances. The
knitting beads are sold in meshes of one hundred and fifty, or
twenty strings, of fifty beads each, of various colours*; and'the large
glass-beads in meshes of twelve strings. There are numerous
manufactories in Germany and Italy of the various kinds of heads,
which are used to a very great extent both in Africa and North and
South America. Germany exports yearly from its- different manu-
facturing places, such as Heidelberg, Nuremberg, fioonenberg,
Meistersdorf, in Bohemia, and Mayence, more than a million
dollars worth. In Venice are large establishmentB "for tibe finest
cut beads. ^.j^
APPENDIX. 169
Nuremberg manu&ctures, besides the glass beads, considerable
quantities of amber beads. In Gablontz, in Bohemia, more than
six thousand persons are engaged in the manufacture of beads, that
are made of pure glass or of a composition. From the glass-
houses, which are very numerous in Bohemia, the rods of different
sizes are delivered to the glass mills for cutting, which is performed
by water power or by hand. In 1828 there were in that neigh-
bourhood one hundred and fifty-two mills in operation ; a number
of glast blowers were likewise engaged, who possess great dexterity
in blowing the small beads with the assistance of a small blow-
table. In the manufactory of George Benedict Barbaria, at Venice,
six hundred varieties of beads are constantly making; and that of
Messrs. Gaspari and Moravia, manufactures, besides the beads,
every article of jewellery from the same material.
The rose beads of Steffansky and Tansig, are made of bread
crumbs, which are beaten up with rose water in a wooden mortar,
until they become a uniform mass, to which is added some otto of
roses and drop-lake, when it is made into beads with dissolved gum
tragacanth ; for the black rose beads, Frankford black is substituted
in the place of the drop-lake.
Lamaire, of France, manufactures beads equal in lustre and
beauty to the real Pearls. He adds to
1000 ounces of glass beads,
3 << fish scales,
I " fine parchment glue,
1 " white wax,
1 " pulverized alabaster,
with which he gives them an external coating.
Rouyer manufactures his beads, also in France, from opal, which
he covers with four or five layers of dissolved isinglass, and then
with a mixture of a fat oil, spirits of turpentine, and copal, so as to
prevent their becoming moist. In order to render them of the
peculiar lustre of the oriental Pearls, they are covered with a
coloured enamel. The opal is fused into rods by a lamp, over
which is laid a brass wire to support it ; the wire is held in one
hand and the opal in the other, and the wire is then kept turning
until the bead hsis the desired size and roundness ; if a coloured
enamel is to be applied, the beads are made but half the required
size, which being done, it is once more covered with the opal, then
X
170 APPENDIX.
the solutkm of ismglass is used, and lastly the yamieh. Beads
made in this manner are with difficalty distinguished from the
oriental Pearls.
The best method of making artificial Pearls, is certainly by
means of pulverized real Pearls. Either the smallest, or the
deformed large specimens, may be reduced to a fine powder, and
then soaked in vinegar or lemon-juice, and the paste made up with
gum tragacauth, may be cut out with a pill machine, or a silver
mould of any desired size, and when a little dry, be enclosed in a
loaf and baited in an oven ; by tin amalgam, or by the silver of
the 0caie» of young fish, the proper lustre may be given.
LXXra. CORALS.
Corab are zoophytes, whose calcarous habitations resemble
vegetable branches. They live in the sea, adhering to rocks, stones,
or vegetables, and shoot to the surface of the water in tubiform
stems with branches, generally coated with a gelatinous or leathery
skin that incloses a cartilaginous marrow, composed of many cells,
inhabited by the animals, who propogate in sprouts from eggs so
fast, that small reef rocks are formed, which in the course of time
grow to islands.
The Red Coral or Precious Coral, {Iris nohilis\ belongs to that
family of zoophytes which live mostly in the cavities of rocks in
the sea ; the stem is always of a beautiful red colour, rarely white ;
quite compact, striated on the outside, of entire calcareous compo-
sition ; it grows one foot high, and an inch thick. The stem is
covered with a leathery crust, containing open warts of eight teeth,
in which the animals, or polypi, with their eight arms, are situated[;
the arms are whimpered, and the animal grows very slowly.
The Red Coral is fished up with nets of strong ropes, fastened
on large wooden cross beams, which are thrown down on the
places where the Corals are known to be fastened, and an expert
diver contrives to entangle the nets in the reefs, which are then
drawn up by force. The Corals so brought up are cleaned, assorted,
and sold to the manufacturers.
The Red Corals are distinguished by the names of the countries
where found.
1. The Barbarian, which are the thickest and purest
APPBNDLS. ITTi:.
2. The Corsican, which are the darkest, but not so thick, and
less pure.
3. The Neapditan, and those from Ponza, which are clear and
pretty thick.
4 The Sardinian, which are thick and clear.
6. The Catalonian, which are nearly as dark as the Condcan,
but mostly thio.
6. The Trapanian Corals, from Trapani, in Sicily, which are
somewhat preferred at Leghorn.
The darkest Corals are most liable to be worm-eaten.
The polished Corals are generally sold in bundles, which consist
of a certain quantity of strings, of a certain weight They are
strung in L^horn, either of various or equal thicknesses, which
latter are then of various sizes, and the bundles receive their names
accordingly ; Grossezze, Mezzanie, Filotti, Capiresti, &c. The
thickest Corals are put up in one string, resembling a tail, and are
called Codini ; the smallest are called SmezzatL
At Genoa, the various large Corals are called Mezzanie ; the
uniform large, Filze ; and the uniform small, Migliari.
According to colour they are distinguished at Leghorn; the
darkest red are called Arcispiuma, which are the dearest ; and then
Primo, Secundo, Terzo, Quarto, Coloro or Sangue, Chiari, Moro,
Nero, &c.
According to form they are called round (tondi), and cylindrical
round {boticelli). The former form are sent to all parts of the
world, whereas the latter are only sent to Poland. The large
Boticelli are put up in meshes of twelve pounds, containing 36
strings ; and the middling size of the Boticelli are in meshes of six
pounds, containing sixty strings; those Boticelli which are still
larger, are called Olivatti, and are only sent to Africa ; those which
are globular, and not drilled, are called Pallini altorno, and are
sent principally to China, where the fitvourite colour is the rose-
red, and the most perfect kind.
The sound Corals are called Netti, and the worm-eaten, Camo-
latti, which latter are mostly sent to the East Indies.
The tops of the branches are called dog-teeth, or dent's cane,
and the thick ends of the branches are called maometti ; holji
kinds are perforated lengthways, and are used in Barbary as ontfi-
ments for horses. The fine large Coral stems which form suitable
172 APPENDIX.
specimens for cabinets of Natural History, are called in Marseilles,
Chouettes.
There are one hundred varieties of shades of Red Coral distin-
guished at Marseilles.
The Corals are principally used for ornaments, and although
not highly esteemed in Europe or this country, are very much so
in the East Indies, China and Africa, where they are preferred to
the Diamond. Almost every East India iady wears a bracelet or
necklace of Corals.
The White Coral has its origin from the eight-star Coral
{madrepora occulta ;) and the Black Coral from the black-horned
Coral {gorgonia antipothes.) The Medusa head {caput medtise^
called the Sea Polen, belongs likewise to the Coral femily, and
consists of sixty-two thousand six hundred and sixty-six articulated
members.
The Corals are fished for on the coast of Barbary, between
Tunis and Algiers ; in (he latter state is Bona, the principal station,
ahd the French have it also at Basteon de France.
The monopoly was purchased by France, in the 17th century,
at eighteen thousand dollars annually, and by England since 1806,
for fifty thousand dollars.
There is at Bona a summer fishery, from the first of April to
the^ first of October, which occupied, in 1821, thirty French,
seventy Sardinian, thirty-nine Tuscanian, eighty-three Neapolitan,
nineteen Sicilian barks ; and, altogether, two hundred barks of
two thousand and twenty-three tons capacity, with two thousand
two hundred and seventy-four men, and they fished up forty-four
thousand two hundred pounds of Coral, valued at two million
fcur hundred thousand francs. The winter fishery of the same
year occupied three French barks, each with nine men, and they
obtained six hundred and eighty pounds of Coral.
The principal manufactories of Corals are now at Leghorn,
where this branch of business has been carried on for two hundred
years past, by the Jews. There were formerly twenty establish-
ments, but the number has lately been much diminished.
They are sent principally to China, the East Indies, and Arabia,
partly by the way of London, and partly by Moscow, Aleppo, and
Alexandria ; many Corals are likewise sent to Poland.
Genoa has a few manufactories, in which the Sardinian Ccials
APPENDIX. 173
are moedy wrought. At Marseilles there has been a large manu-
fectory ever since 1780, and a,t present it is the only establishment
of the kind in France.
The East Indies consume, according to the statement of Le
Goux de Haix, nearly four million francs worth.
Corals are worn in the East as ornameuts in the turbans, and
the Arabs bury the Coral with their dead.
A large Co^al, from the manufactory at Marseilles, was sold in
China, to a Mandarin, for twenty thousand dollars.
The price of Coral has, within some years, much depreciated.
■-■■*
■ •
»
CONTENTS.
Adnlaria
IS
Brazilian Topaz
TS
Agale
10-.
Brazilian Tourmaline
90
Agaie, Chalcedony
102
Brecciated Porphyry
166
Alsbaater
140
Brilliants
4U
Almaadine Ruby
140
BriUionets
411
77
Bristol Marble
166
Amazon Stone
123
Brown Uuartz
99
Amber
141
Cabochon Cut
43
American Marble
163
Cacheloug
118
Amethyst
94
Cairngouiam
92
Anthracite Coal
147
Calcareous Spar
49
Aiitiijue Porphyry
15S
Cannel Coal
147
Apatite
15l>
Carara Marble
162
Aplome
87
Oarneleon
103
Apoade Gems
31
Onyx
103
Appendix
163
Cat Sapphire
70
Apyrite
90
Cat's Eye.
97
Aquamarine
83
Caves in North America
160
Aquamarine ChryeoUte
84
Ceregat
94
Amazon Stone
123
Ceylonian Crysolite
90
Anificial Aquamarine
60
Opal
112
Emerald
50
Touimaline
90
Pearia
168
Chalcedony
101
Ruby
49
Chalcedonyx
102
Sapphire
50
Change of colour of Gems
24
Syrian Garnet
60
Chemical Character «
2T
Topaz
49
Compoeition "
27
Aogite Sienite
160
riiloropliane
139
Avantuirae
99
Ctirysoberyl
76
Axinite
121
Chrysolite
76
Beryl
83
Chrysoprase
109
Black Amber
146
Cifinamon Stone
89
Black Glaa Lava
120
Circle Agate
106
Bloodstone
104
Citron
92
Bohemian Diamond
92
Cleaning of Gems
48
Garnet
87
Cleavage of Geme
36
Topaz
92
Minerals
13
Botllestone
120
Cloudy Agate
106
Brazilian Emerald -
90
■ — Chalcedony
102
aipphir.
78
Cohe8ioao£Qk«a)&
%S
176
CONTENTS.
Colouring materials
T3
French Shell Marble
iTs
Colour of Gems
17
Garnet
86
Common Corrundum
7-4
Gem Grinder
35
Felspar
123
Gems for Optical purposes
52
Opal
116
Geographical dialiibution
28
Q,uaru
96
Geological Character of Gems 28
43
Glyptic Art
32
Corals
170
Gold Stone
99
Coral Agate
106
Goutte d' Eau
78
Cordierite
U2
de Sang
77
Cornalines de vielle roch
103
Girasol Sapphire
70
Corundum
60
Granite
160
Dariain^ir Diamond
34
Green Mica
167
Definition of Gema
9
Grinding of Gema
34
Dendrilic Agate
106
Materials
45
Derbyshire Spar
137
Hair Stone
93
Diamond Grinder
3S
Haayne
123
Diamond
63
Hard Gems
16
Dichroile
112
Hardr»Bj of Minerals
13
Division of Gems
27
Hatchet Stone
147
Minerals
9
Heliotrope
104
Drilling of Gems
45
History of Gems
30
Doublets
61
Hornstone
101
Double facet cut
43
Hyacinth
89
Egyptian Jasper
100
Hydrophane
117
Pebble
101)
HyperBttiene
127
Marble
162
Iceland Agate
120
— Essoniie
89
Idocra.e
128
Electric Schorl
90
Imitation of Gems
48
Elongated facet cut
42
Indian Topaz
78
Emerald
60
Indicolite
90
Fngraving of Gems
44
lolite
112
External oharacters of
IiideBcence of Gems
24
Minerals
10
Iridescent t^uartz
92
Eye Agate
106
Italian Marble
•162
Eye Stone
106
SheU Marble
164
Felspar
122
Jade
147
Figure Agate
106
Jasper
99
Fish Eye
113
Opal
119
Fluorspar
136
Jet
146
Fortification Agate
106
Jewellery Grinder
36
Fire Opal
116
Jeweller's Wax
43
Fracture of minerals
13
Kyanite
132
Frawinent Agate
106
Kuinw Diamond
34
Forms of Diamond
39
Labrador
125
Gema
41
Laconia Marble
125
11
liaodscape Agate
98
CONTENTS.
17T
LapisLazuli
Lapidary's Apparatus
Largest Diamonds
Sapphires
Lava
Lepidolite
Limestone
Lombardy Marble
Loss of Colour of Gtems
Love's Arrow
Lumachelle Marble
Luui "
Lustre of Gems
Lustre Shine of Gems
Magnetism of Gems
Male Sapphire
Malachite
Marble
Marakenite
Markasite
Mica
Mixed Facet Cut
Moon Stone
Moccha Stones
Moss Agate
Natrolite
Natural History
Needle Stone
Nephrite
New-Haven Marble
Nomenclature of Gems
Oberstein
Obsidian
Occidental Diamond
Topaz
Onyx
OoHte
Opal
Oriental Amethyst
Aquamarine
Chrysolite
Emerald
Hyacinth
Ruby
Sapphire
Topaz
Panno di Morto
Page.
129
43
65
74
147
156
149
152
25
93
154
152
22
25
26
70
138
149
120
X57
156
42
123
102
106
135
9
93
147
153
29
107
119
92
92
103
155
134
70
70
70
70
70
69
70
70
155
Pstetes
Pavilion Cut
Pearls
Peliome
Petrefact Agate
Philadelphia Marble
Phosphwescence of GreAas
Pisolite
Pilch Opal
-^ — Coal
Plaster of Paris
Plasma
Play of Colour of Qems
Phimose Mica
Polishing Materials
Porphyry
Porphyritic Sienite
Potomac Marble
Prase
Precious Gems
Opal
Serpentine
Price of Gems
Sapphire
Pseudo Diamond
Punctated Agate
Puuamu
Pyrites
Quartz
Rainbow Agate
Chalcedony
Raising the Colour of GenM
Red Sapphire
Refraction of Gems
Regent Diamond
Ribband Jaspar
Rock Crystal
Rock of Gibraltar
Rose Diamond
Manganese
— ■ — Quartz
Rosso Aolico
Rubellite
Ruby Spinelle
Ruin Agate
Sapphire
42
163
112
106
103
95
155
IIT
146
141
102
24
157
46
168
160
163
98
9
113
148
51
72
92
106
147
167
91
106
102
46
69
23
36
100
86
155
38
157
96
152
60
76
106
178
CONTENTS.
Fan.
Sardonyx 103
Satin Gypsum 141
Spar 139
Sawing of Crems 45
Saxon Topaz 78
Scale of Hardness 13
Scotch Pebble 92
Sculpture in Gems 32
Semi-Camelion 102
Hard Gems 15
Opal 118
Serpentine 148
Setting of Gems 47
Shell Agate 106
Marble 154
Siberian Aquamarine 84
Topaz 78
I'ourmaline 90
Siberite 90
Sienite 159
Smell of Gems 26
Smoky Quartz 92
Topaz 92
Soft Precious Stones 15
Specific Gravity of Gems 16
Spinelle 76
St Stephen's Stone 102
Stalactite 149
Stalagmite 149
Star Agate 106
Sapphire 70
SteinheiUte 112
Strass 48
Striped Jasper
Sulphuret of Iron
Sun Stone 70
Surface of Minerals
Syrian Garnet
Table of Colours
Out
Diamond
Taste of Gems
Thumerstone
Topaz
Touch of Gems
Tourmaline
Trade in Gems
Transparency of Gems
Tree Stones
Tube Agate
Turquoise
Ultramarine
Artificial
Yenitian Marble
Venus Hair
Verde Antico
Vitreous Felspar
Volcanic Lava
Water Drops
Opal
Sapphire
Wax Opal
White Sapphire
Yellow Jasper
Quartz
Zircon
Pace.
100
157
and 122
14
87
18
43
41
46
121
77
26
89
51
23
102
106
133
130
131
162
93
163
122
147
78
22
70
117
70
100
92
85
NOTICE TO THE PUBLIC.
The Author of the foregdng Treatise^ has in preparation, and
will shortly be ready for the press, the following works viz : —
DOMESTIC GUIDE, for the preparation of Cosmetics, and
substances of every description for Washing, Bleaching, Cleaning,
and Polishing : in which the author has collected all the informa-
tion of others, with his own long experience, and has demonstrated
all the principles of the above practical branches by their natural
causes and effects. The whole work will contain upwards of 200
octavo pages and 2000 receipts.
ALSO,
MINERALOGICAL TEXT-BOOK for schools, Seminaries
and Private Students.
This Book is intended to explain the Elements of Minemlogy
by their external and internal characters, without depending, how-
ever, altogether, upon the crystallographical distinctions, but with
particular reference to their localities and application to the useful
arts.
This work does not intend to be strictly philosophical, as it is
a plain Text Book for the younger student, who wishes to be
informed of the elementary principles, how to collect, and how
to classify the minerals coming under his observation.
ADVERTISEMENT.
The Subscriber takes this method of informing his friends and
the pubUc at a distance, that he continues to manufacture German
Silver equal, in every respect, in durability and colour, to that
originally made in Germany, which has now attained so high a
reputation in Europe.
The first introduction of this metal here was by the subscriber,
nine years ago, previous to which the material was altogether
unknown. He regrets here to have occasion to caution the public
against a spurious article that is extensively imported, which, by
its colour, is easily detected, assuming more tne appearance of
brass than pure silver. The metal, when manufactured into ware,
is allowed, by every competent judge, to be .far preferable to silver-
plated metal, inasmuch as it improves by use and cleaning,
whereas the silver-plated metal in a short time loses its silver-
plating and becomes worthless.
At the Subscriber's store may be seen an extensive assortment
of the undermentioned articles, which are all made from his own
composition, which he takes a pleasure in recommending to the
attention of his friends.
Grerman Silver in sheets, wire and castings of almost every
description.
Table, Tea, Dessert, Salt, Gravy, Mhfstard, and Cream Spoons ;
Table and Desert Forks.
Speaking-trumpets for Firemen and Sea Captains, after the
pattern of Capt. Ross.
Butter, Cheese, and Dessert Knives; Stair-Rods, Pitchers, Mugs,
Castors, Taps for Buttlers, Door and Number-plates, Lock and
Gun Trimmings in complete sets, Tea Sets, Muddlers, Thimbles,
Sugar Tongs, Church Service, Napkin Rings,Night-lamps, Candle-
sticks, Coffin-plates, &c. &c. &c.
Chemicals of the rarest description, warranted perfectly pure,
for Colleges and Scientific Institutions are always in store, and can
readily be forwarded to any part of the United States. Likewise
the more common chemicals, suitable for wholsale druggists, will
at all times be forwarded at the shortest notice, and at lowest prices.
Dr. Lewis Feuchtwanger,
No. 2 Courtlandt-streeU
(fl
DATE DUE 1
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